The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.
The use of statistical and mathematical methods to analyze biological observations and phenomena.
Refraction of LIGHT effected by the media of the EYE.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
The space in the eye, filled with aqueous humor, bounded anteriorly by the cornea and a small portion of the sclera and posteriorly by a small portion of the ciliary body, the iris, and that part of the crystalline lens which presents through the pupil. (Cline et al., Dictionary of Visual Science, 4th ed, p109)
Measurement of distances or movements by means of the phenomena caused by the interference of two rays of light (optical interferometry) or of sound (acoustic interferometry).
The condition of where images are correctly brought to a focus on the retina.
A refractive error in which rays of light entering the eye parallel to the optic axis are brought to a focus behind the retina, as a result of the eyeball being too short from front to back. It is also called farsightedness because the near point is more distant than it is in emmetropia with an equal amplitude of accommodation. (Dorland, 27th ed)
The white, opaque, fibrous, outer tunic of the eyeball, covering it entirely excepting the segment covered anteriorly by the cornea. It is essentially avascular but contains apertures for vessels, lymphatics, and nerves. It receives the tendons of insertion of the extraocular muscles and at the corneoscleral junction contains the canal of Schlemm. (From Cline et al., Dictionary of Visual Science, 4th ed)
Biological action and events that support the functions of the EYE and VISION, OCULAR.
An alternative to REFRACTIVE SURGICAL PROCEDURES. A therapeutic procedure for correcting REFRACTIVE ERRORS. It involves wearing CONTACT LENSES designed to force corrective changes to the curvature of the CORNEA that remain after the lenses are removed. The effect is temporary but is maintained by wearing the therapeutic lenses daily, usually during sleep.
Measurements of the height, weight, length, area, etc., of the human and animal body or its parts.
Processes and properties of the EYE as a whole or of any of its parts.
An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.
The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)
The pressure of the fluids in the eye.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
Artificial implanted lenses.
Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)
Absence of crystalline lens totally or partially from field of vision, from any cause except after cataract extraction. Aphakia is mainly congenital or as result of LENS DISLOCATION AND SUBLUXATION.
Excessive axial myopia associated with complications (especially posterior staphyloma and CHOROIDAL NEOVASCULARIZATION) that can lead to BLINDNESS.
A pair of ophthalmic lenses in a frame or mounting which is supported by the nose and ears. The purpose is to aid or improve vision. It does not include goggles or nonprescription sun glasses for which EYE PROTECTIVE DEVICES is available.
A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.
Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.
A form of glaucoma in which the intraocular pressure increases because the angle of the anterior chamber is blocked and the aqueous humor cannot drain from the anterior chamber.
The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.
Diseases affecting the eye.
Insertion of an artificial lens to replace the natural CRYSTALLINE LENS after CATARACT EXTRACTION or to supplement the natural lens which is left in place.
The absence or restriction of the usual external sensory stimuli to which the individual responds.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
An objective determination of the refractive state of the eye (NEARSIGHTEDNESS; FARSIGHTEDNESS; ASTIGMATISM). By using a RETINOSCOPE, the amount of correction and the power of lens needed can be determined.
Voluntary or reflex-controlled movements of the eye.
General disorders of the sclera or white of the eye. They may include anatomic, embryologic, degenerative, or pigmentation defects.
The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.
The removal of a cataractous CRYSTALLINE LENS from the eye.
Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)
The professional practice of primary eye and vision care that includes the measurement of visual refractive power and the correction of visual defects with lenses or glasses.
Organic siloxanes which are polymerized to the oily stage. The oils have low surface tension and density less than 1. They are used in industrial applications and in the treatment of retinal detachment, complicated by proliferative vitreoretinopathy.
An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)
A condition of an inequality of refractive power of the two eyes.
The dioptric adjustment of the EYE (to attain maximal sharpness of retinal imagery for an object of regard) referring to the ability, to the mechanism, or to the process. Ocular accommodation is the effecting of refractive changes by changes in the shape of the CRYSTALLINE LENS. Loosely, it refers to ocular adjustments for VISION, OCULAR at various distances. (Cline et al., Dictionary of Visual Science, 4th ed)
I'm sorry for any confusion, but "Singapore" is not a medical term or concept, it's a country in Southeast Asia. If you have any questions about medical topics, I'd be happy to try and help!
A procedure for removal of the crystalline lens in cataract surgery in which an anterior capsulectomy is performed by means of a needle inserted through a small incision at the temporal limbus, allowing the lens contents to fall through the dilated pupil into the anterior chamber where they are broken up by the use of ultrasound and aspirated out of the eye through the incision. (Cline, et al., Dictionary of Visual Science, 4th ed & In Focus 1993;1(1):1)
A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.
Congenital absence of or defects in structures of the eye; may also be hereditary.
Color of the iris.
Congenital or developmental anomaly in which the eyeballs are abnormally small.
Examination of the interior of the eye with an ophthalmoscope.
The back two-thirds of the eye that includes the anterior hyaloid membrane and all of the optical structures behind it: the VITREOUS HUMOR; RETINA; CHOROID; and OPTIC NERVE.
The period of confinement of a patient to a hospital or other health facility.
Unequal curvature of the refractive surfaces of the eye. Thus a point source of light cannot be brought to a point focus on the retina but is spread over a more or less diffuse area. This results from the radius of curvature in one plane being longer or shorter than the radius at right angles to it. (Dorland, 27th ed)
The aperture in the iris through which light passes.
Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.
The theory that human CHARACTER and BEHAVIOR are shaped by the GENES that comprise the individual's GENOTYPE rather than by CULTURE; ENVIRONMENT; and individual choice.
Agents that dilate the pupil. They may be either sympathomimetics or parasympatholytics.
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Individuals whose ancestral origins are in the southeastern and eastern areas of the Asian continent.
Presence of an intraocular lens after cataract extraction.
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
A scientific tool based on ULTRASONOGRAPHY and used not only for the observation of microstructure in metalwork but also in living tissue. In biomedical application, the acoustic propagation speed in normal and abnormal tissues can be quantified to distinguish their tissue elasticity and other properties.
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
The distance between the anterior and posterior poles of the eye, measured either by ULTRASONOGRAPHY or by partial coherence interferometry.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
A parasympatholytic anticholinergic used solely to obtain mydriasis or cycloplegia.
Corneal and conjunctival dryness due to deficient tear production, predominantly in menopausal and post-menopausal women. Filamentary keratitis or erosion of the conjunctival and corneal epithelium may be caused by these disorders. Sensation of the presence of a foreign body in the eye and burning of the eyes may occur.
A method of stopping internal bleeding or blood flow, or the closure of a wound or body cavity, achieved by applying pressure or introducing an absorbent liquid, gel, or tampon.
The front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.
Examination of the angle of the anterior chamber of the eye with a specialized optical instrument (gonioscope) or a contact prism lens.
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
Separation of the inner layers of the retina (neural retina) from the pigment epithelium. Retinal detachment occurs more commonly in men than in women, in eyes with degenerative myopia, in aging and in aphakia. It may occur after an uncomplicated cataract extraction, but it is seen more often if vitreous humor has been lost during surgery. (Dorland, 27th ed; Newell, Ophthalmology: Principles and Concepts, 7th ed, p310-12).
Images seen by one eye.
Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)
A genus of tree shrews of the family TUPAIIDAE which consists of about 12 species. One of the most frequently encountered species is T. glis. Members of this genus inhabit rain forests and secondary growth areas in southeast Asia.
Removal of the whole or part of the vitreous body in treating endophthalmitis, diabetic retinopathy, retinal detachment, intraocular foreign bodies, and some types of glaucoma.
The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.
Measurement of the index of refraction (the ratio of the velocity of light or other radiation in the first of two media to its velocity in the second as it passes from one into the other).
A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
Diseases of the cornea.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Absence of the crystalline lens resulting from cataract extraction.
Injury to any part of the eye by extreme heat, chemical agents, or ultraviolet radiation.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)
Descriptive anatomy based on three-dimensional imaging (IMAGING, THREE-DIMENSIONAL) of the body, organs, and structures using a series of computer multiplane sections, displayed by transverse, coronal, and sagittal analyses. It is essential to accurate interpretation by the radiologist of such techniques as ultrasonic diagnosis, MAGNETIC RESONANCE IMAGING, and computed tomography (TOMOGRAPHY, X-RAY COMPUTED). (From Lane & Sharfaei, Modern Sectional Anatomy, 1992, Preface)
Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. Many types are available, including continuous and extended-wear versions, which are gas-permeable and easily sterilized.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.
The surgical removal of the eyeball leaving the eye muscles and remaining orbital contents intact.
The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
The inner layer of CHOROID, also called the lamina basalis choroideae, located adjacent to the RETINAL PIGMENT EPITHELIUM; (RPE) of the EYE. It is a membrane composed of the basement membranes of the choriocapillaris ENDOTHELIUM and that of the RPE. The membrane stops at the OPTIC NERVE, as does the RPE.
A bilateral retinopathy occurring in premature infants treated with excessively high concentrations of oxygen, characterized by vascular dilatation, proliferation, and tortuosity, edema, and retinal detachment, with ultimate conversion of the retina into a fibrous mass that can be seen as a dense retrolental membrane. Usually growth of the eye is arrested and may result in microophthalmia, and blindness may occur. (Dorland, 27th ed)
Retinal diseases refer to a diverse group of vision-threatening disorders that affect the retina's structure and function, including age-related macular degeneration, diabetic retinopathy, retinal detachment, retinitis pigmentosa, and macular edema, among others.
A country spanning from central Asia to the Pacific Ocean.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)
Introduction of substances into the body using a needle and syringe.
Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.
Centers for storing various parts of the eye for future use.
Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
Blockage of the RETINAL VEIN. Those at high risk for this condition include patients with HYPERTENSION; DIABETES MELLITUS; ATHEROSCLEROSIS; and other CARDIOVASCULAR DISEASES.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
Disorders affecting TWINS, one or both, at any age.
The single layer of pigment-containing epithelial cells in the RETINA, situated closely to the tips (outer segments) of the RETINAL PHOTORECEPTOR CELLS. These epithelial cells are macroglia that perform essential functions for the photoreceptor cells, such as in nutrient transport, phagocytosis of the shed photoreceptor membranes, and ensuring retinal attachment.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
Tumors or cancer of the EYE.
A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.
The period following a surgical operation.
Light sensory organ in ARTHROPODS consisting of a large number of ommatidia, each functioning as an independent photoreceptor unit.
Two offspring from the same PREGNANCY. They are from two OVA, fertilized at about the same time by two SPERMATOZOA. Such twins are genetically distinct and can be of different sexes.
Personal devices for protection of the eyes from impact, flying objects, glare, liquids, or injurious radiation.
Two off-spring from the same PREGNANCY. They are from a single fertilized OVUM that split into two EMBRYOS. Such twins are usually genetically identical and of the same sex.
The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.
The measurement of an organ in volume, mass, or heaviness.
An infant during the first month after birth.
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
Deeply perforating or puncturing type intraocular injuries.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.
Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.
Inanimate objects that become enclosed in the eye.
Methods and procedures for recording EYE MOVEMENTS.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.
Elements of limited time intervals, contributing to particular results or situations.
The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.
Infection, moderate to severe, caused by bacteria, fungi, or viruses, which occurs either on the external surface of the eye or intraocularly with probable inflammation, visual impairment, or blindness.
Refers to animals in the period of time just after birth.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
The clear, watery fluid which fills the anterior and posterior chambers of the eye. It has a refractive index lower than the crystalline lens, which it surrounds, and is involved in the metabolism of the cornea and the crystalline lens. (Cline et al., Dictionary of Visual Science, 4th ed, p319)
A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.
Infections in the inner or external eye caused by microorganisms belonging to several families of bacteria. Some of the more common genera found are Haemophilus, Neisseria, Staphylococcus, Streptococcus, and Chlamydia.
A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.
The blending of separate images seen by each eye into one composite image.
Eye movements that are slow, continuous, and conjugate and occur when a fixed object is moved slowly.
A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.
Infections of the eye caused by minute intracellular agents. These infections may lead to severe inflammation in various parts of the eye - conjunctiva, iris, eyelids, etc. Several viruses have been identified as the causative agents. Among these are Herpesvirus, Adenovirus, Poxvirus, and Myxovirus.
Individuals whose ancestral origins are in the continent of Europe.
Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132).
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.
The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.
The mucous membrane that covers the posterior surface of the eyelids and the anterior pericorneal surface of the eyeball.
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Each of the upper and lower folds of SKIN which cover the EYE when closed.
Infection by a variety of fungi, usually through four possible mechanisms: superficial infection producing conjunctivitis, keratitis, or lacrimal obstruction; extension of infection from neighboring structures - skin, paranasal sinuses, nasopharynx; direct introduction during surgery or accidental penetrating trauma; or via the blood or lymphatic routes in patients with underlying mycoses.
Specialized cells in the invertebrates that detect and transduce light. They are predominantly rhabdomeric with an array of photosensitive microvilli. Illumination depolarizes invertebrate photoreceptors by stimulating Na+ influx across the plasma membrane.
Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.
A dull or sharp painful sensation associated with the outer or inner structures of the eyeball, having different causes.
Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)
The surgical removal of the inner contents of the eye, leaving the sclera intact. It should be differentiated from ORBIT EVISCERATION which removes the entire contents of the orbit, including eyeball, blood vessels, muscles, fat, nerve supply, and periosteum.
A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
Intraocular hemorrhage from the vessels of various tissues of the eye.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
The detection of RESTRICTION FRAGMENT LENGTH POLYMORPHISMS by selective PCR amplification of restriction fragments derived from genomic DNA followed by electrophoretic analysis of the amplified restriction fragments.
Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.
A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Recording of electric potentials in the retina after stimulation by light.
The loss of some TELOMERE sequence during DNA REPLICATION of the first several base pairs of a linear DNA molecule; or from DNA DAMAGE. Cells have various mechanisms to restore length (TELOMERE HOMEOSTASIS.) Telomere shortening is involved in the progression of CELL AGING.
Maintenance of TELOMERE length. During DNA REPLICATION, chromosome ends loose some of their telomere sequence (TELOMERE SHORTENING.) Various cellular mechanism are involved in repairing, extending, and recapping the telomere ends.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
The properties, processes, and behavior of biological systems under the action of mechanical forces.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The turning inward of the lines of sight toward each other.
Surgery performed on the eye or any of its parts.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Voluntary or involuntary motion of head that may be relative to or independent of body; includes animals and humans.
Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.
The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.
The selecting and organizing of visual stimuli based on the individual's past experience.
A reflex wherein impulses are conveyed from the cupulas of the SEMICIRCULAR CANALS and from the OTOLITHIC MEMBRANE of the SACCULE AND UTRICLE via the VESTIBULAR NUCLEI of the BRAIN STEM and the median longitudinal fasciculus to the OCULOMOTOR NERVE nuclei. It functions to maintain a stable retinal image during head rotation by generating appropriate compensatory EYE MOVEMENTS.

Human optical axial length and defocus. (1/93)

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Ethnic differences in the prevalence of myopia and ocular biometry in 10- and 11-year-old children: the Child Heart and Health Study in England (CHASE). (2/93)

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Hyperopic refractive error and shorter axial length are associated with age-related macular degeneration: the Singapore Malay Eye Study. (3/93)

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In vivo measurement of blood velocity in human major retinal vessels using the laser speckle method. (4/93)

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Relative peripheral refractive error and the risk of onset and progression of myopia in children. (5/93)

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Influence of refractive error and axial length on retinal vessel geometric characteristics. (6/93)

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Axial length of myopia: a review of current research. (7/93)

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Axial length measurements by contact and immersion techniques in pediatric eyes with cataract. (8/93)

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The eye is the organ of sight, primarily responsible for detecting and focusing on visual stimuli. It is a complex structure composed of various parts that work together to enable vision. Here are some of the main components of the eye:

1. Cornea: The clear front part of the eye that refracts light entering the eye and protects the eye from harmful particles and microorganisms.
2. Iris: The colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.
3. Pupil: The opening in the center of the iris that allows light to enter the eye.
4. Lens: A biconvex structure located behind the iris that further refracts light and focuses it onto the retina.
5. Retina: A layer of light-sensitive cells (rods and cones) at the back of the eye that convert light into electrical signals, which are then transmitted to the brain via the optic nerve.
6. Optic Nerve: The nerve that carries visual information from the retina to the brain.
7. Vitreous: A clear, gel-like substance that fills the space between the lens and the retina, providing structural support to the eye.
8. Conjunctiva: A thin, transparent membrane that covers the front of the eye and the inner surface of the eyelids.
9. Extraocular Muscles: Six muscles that control the movement of the eye, allowing for proper alignment and focus.

The eye is a remarkable organ that allows us to perceive and interact with our surroundings. Various medical specialties, such as ophthalmology and optometry, are dedicated to the diagnosis, treatment, and management of various eye conditions and diseases.

Myopia, also known as nearsightedness, is a common refractive error of the eye. It occurs when the eye is either too long or the cornea (the clear front part of the eye) is too curved. As a result, light rays focus in front of the retina instead of directly on it, causing distant objects to appear blurry while close objects remain clear.

Myopia typically develops during childhood and can progress gradually or rapidly until early adulthood. It can be corrected with glasses, contact lenses, or refractive surgery such as LASIK. Regular eye examinations are essential for people with myopia to monitor any changes in their prescription and ensure proper correction.

While myopia is generally not a serious condition, high levels of nearsightedness can increase the risk of certain eye diseases, including cataracts, glaucoma, retinal detachment, and myopic degeneration. Therefore, it's crucial to manage myopia effectively and maintain regular follow-ups with an eye care professional.

Biometry, also known as biometrics, is the scientific study of measurements and statistical analysis of living organisms. In a medical context, biometry is often used to refer to the measurement and analysis of physical characteristics or features of the human body, such as height, weight, blood pressure, heart rate, and other physiological variables. These measurements can be used for a variety of purposes, including diagnosis, treatment planning, monitoring disease progression, and research.

In addition to physical measurements, biometry may also refer to the use of statistical methods to analyze biological data, such as genetic information or medical images. This type of analysis can help researchers and clinicians identify patterns and trends in large datasets, and make predictions about health outcomes or treatment responses.

Overall, biometry is an important tool in modern medicine, as it allows healthcare professionals to make more informed decisions based on data and evidence.

Ocular refraction is a medical term that refers to the bending of light as it passes through the optical media of the eye, including the cornea and lens. This process allows the eye to focus light onto the retina, creating a clear image. The refractive power of the eye is determined by the curvature and transparency of these structures.

In a normal eye, light rays are bent or refracted in such a way that they converge at a single point on the retina, producing a sharp and focused image. However, if the curvature of the cornea or lens is too steep or too flat, the light rays may not converge properly, resulting in a refractive error such as myopia (nearsightedness), hyperopia (farsightedness), or astigmatism.

Ocular refraction can be measured using a variety of techniques, including retinoscopy, automated refraction, and subjective refraction. These measurements are used to determine the appropriate prescription for corrective lenses such as eyeglasses or contact lenses. In some cases, ocular refractive errors may be corrected surgically through procedures such as LASIK or PRK.

Refractive errors are a group of vision conditions that include nearsightedness (myopia), farsightedness (hyperopia), astigmatism, and presbyopia. These conditions occur when the shape of the eye prevents light from focusing directly on the retina, causing blurred or distorted vision.

Myopia is a condition where distant objects appear blurry while close-up objects are clear. This occurs when the eye is too long or the cornea is too curved, causing light to focus in front of the retina instead of directly on it.

Hyperopia, on the other hand, is a condition where close-up objects appear blurry while distant objects are clear. This happens when the eye is too short or the cornea is not curved enough, causing light to focus behind the retina.

Astigmatism is a condition that causes blurred vision at all distances due to an irregularly shaped cornea or lens.

Presbyopia is a natural aging process that affects everyone as they get older, usually around the age of 40. It causes difficulty focusing on close-up objects and can be corrected with reading glasses, bifocals, or progressive lenses.

Refractive errors can be diagnosed through a comprehensive eye exam and are typically corrected with eyeglasses, contact lenses, or refractive surgery such as LASIK.

The anterior chamber is the front portion of the eye, located between the cornea (the clear front "window" of the eye) and the iris (the colored part of the eye). It is filled with a clear fluid called aqueous humor that provides nutrients to the structures inside the eye and helps maintain its shape. The anterior chamber plays an important role in maintaining the overall health and function of the eye.

Interferometry is not specifically a medical term, but it is used in certain medical fields such as ophthalmology and optics research. Here is a general definition:

Interferometry is a physical method that uses the interference of waves to measure the differences in phase between two or more waves. In other words, it's a technique that combines two or more light waves to create an interference pattern, which can then be analyzed to extract information about the properties of the light waves, such as their wavelength, amplitude, and phase.

In ophthalmology, interferometry is used in devices like wavefront sensors to measure the aberrations in the eye's optical system. By analyzing the interference pattern created by the light passing through the eye, these devices can provide detailed information about the shape and curvature of the cornea and lens, helping doctors to diagnose and treat various vision disorders.

In optics research, interferometry is used to study the properties of light waves and materials that interact with them. By analyzing the interference patterns created by light passing through different materials or devices, researchers can gain insights into their optical properties, such as their refractive index, thickness, and surface roughness.

Emmetropia is a term used in optometry and ophthalmology to describe a state where the eye's optical power is perfectly matched to the length of the eye. As a result, light rays entering the eye are focused directly on the retina, creating a clear image without the need for correction with glasses or contact lenses. It is the opposite of myopia (nearsightedness), hyperopia (farsightedness), or astigmatism, where the light rays are not properly focused on the retina, leading to blurry vision. Emmetropia is considered a normal and ideal eye condition.

Hyperopia, also known as farsightedness, is a refractive error in which the eye does not focus light directly on the retina when looking at a distant object. Instead, light is focused behind the retina, causing close-up objects to appear blurry. This condition usually results from the eyeball being too short or the cornea having too little curvature. It can be corrected with eyeglasses, contact lenses, or refractive surgery.

The sclera is the tough, white, fibrous outer coating of the eye in humans and other vertebrates, covering about five sixths of the eyeball's surface. It provides protection for the delicate inner structures of the eye and maintains its shape. The sclera is composed mainly of collagen and elastic fiber, making it strong and resilient. Its name comes from the Greek word "skleros," which means hard.

Ocular physiological processes refer to the various functional activities and mechanisms that occur within the eye, which are essential for proper vision and eye health. These processes include:

1. Aqueous Humor Dynamics: The production, circulation, and drainage of a clear fluid called aqueous humor inside the eye, maintaining intraocular pressure.
2. Refraction and Accommodation: The bending of light rays as they pass through the cornea and lens to focus on the retina, along with the ability of the lens to change shape for near and far vision (accommodation).
3. Retinal Processing: The conversion of light energy into electrical signals by photoreceptor cells (rods and cones) in the retina, followed by signal processing and transmission through retinal ganglion cells to the optic nerve.
4. Optic Nerve Transmission: The transmission of visual information from the retina to the brain via the optic nerve, where it is further processed and interpreted as visual perception.
5. Pupillary Light Reflex: The automatic adjustment of pupil size in response to changes in light intensity, allowing for optimal light entry into the eye.
6. Extraocular Muscle Function: The coordinated movement of six extrinsic muscles that control eyeball rotation and alignment, ensuring proper fixation and tracking of visual targets.
7. Lacrimal System Function: The production, distribution, and drainage of tears to keep the ocular surface lubricated and protected from external irritants.
8. Blink Reflex and Tear Film Maintenance: The regular blinking that distributes tear film over the eye surface, protecting it from drying out and maintaining its optical clarity.
9. Circadian Rhythm Regulation: The internal regulation of sleep-wake cycles, hormonal release, and other physiological processes in response to light exposure.

Understanding ocular physiological processes is crucial for diagnosing and treating various eye conditions and diseases, as well as for developing new therapies and treatments to improve vision and overall eye health.

Orthokeratology, often referred to as "ortho-k," is a non-surgical procedure that uses specially designed contact lenses to temporarily reshape the cornea (the clear, dome-shaped surface at the front of the eye). The goal of orthokeratology is to flatten the cornea slightly so that it can properly focus light onto the retina and improve vision.

During an orthokeratology procedure, a patient wears specially fitted contact lenses while they sleep. These lenses gently reshape the cornea overnight, allowing the patient to see clearly during the day without needing glasses or contact lenses. The effects of orthokeratology are usually reversible and may wear off if the patient stops wearing the contact lenses regularly.

Orthokeratology is often used as an alternative to refractive surgery for people who want to correct their vision without undergoing a surgical procedure. It can be particularly useful for individuals with mild to moderate myopia (nearsightedness) and astigmatism, although it may also be used to treat other refractive errors.

It's important to note that orthokeratology is not a permanent solution for vision problems, and it does carry some risks, such as eye infections and corneal abrasions. As with any medical procedure, it's essential to consult with an eye care professional to determine whether orthokeratology is the right choice for you.

"Body weights and measures" is a general term that refers to the various methods used to quantify an individual's physical characteristics, particularly those related to health and fitness. This can include:

1. Body weight: The total amount of weight that a person's body possesses, typically measured in pounds or kilograms.
2. Height: The vertical distance from the bottom of the feet to the top of the head, usually measured in inches or centimeters.
3. Blood pressure: The force exerted by the blood on the walls of the arteries as it circulates through the body, typically measured in millimeters of mercury (mmHg).
4. Body mass index (BMI): A measure of body fat based on an individual's weight and height, calculated by dividing a person's weight in kilograms by their height in meters squared.
5. Waist circumference: The distance around the narrowest part of the waist, typically measured at the level of the belly button.
6. Hip circumference: The distance around the widest part of the hips, usually measured at the level of the greatest protrusion of the buttocks.
7. Blood glucose levels: The concentration of glucose in the blood, typically measured in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).
8. Cholesterol levels: The amount of cholesterol present in the blood, usually measured in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).

These and other body weights and measures are commonly used by healthcare professionals to assess an individual's health status, identify potential health risks, and guide treatment decisions.

"Ocular physiological phenomena" is not a standardized medical term with a specific definition. However, I can provide some examples of ocular physiological phenomena, which refer to various normal functions and processes that occur in the eye. Here are a few examples:

1. Accommodation: The ability of the eye to change optical power to maintain a clear image or focus on an object as its distance varies. This is primarily achieved by changing the curvature of the lens through the action of the ciliary muscles.
2. Pupillary reflex: The automatic adjustment of the pupil's size in response to changes in light intensity. In bright light, the pupil constricts (miosis), while in dim light, it dilates (mydriasis). This reflex helps regulate the amount of light that enters the eye.
3. Tear production: The continuous secretion of tears by the lacrimal glands to keep the eyes moist and protected from dust, microorganisms, and other foreign particles.
4. Extraocular muscle function: The coordinated movement of the six extraocular muscles that control eyeball rotation and enable various gaze directions.
5. Color vision: The ability to perceive and distinguish different colors based on the sensitivity of photoreceptor cells (cones) in the retina to specific wavelengths of light.
6. Dark adaptation: The process by which the eyes adjust to low-light conditions, improving visual sensitivity primarily through changes in the rod photoreceptors' sensitivity and pupil dilation.
7. Light adaptation: The ability of the eye to adjust to different levels of illumination, mainly through alterations in pupil size and photoreceptor cell response.

These are just a few examples of ocular physiological phenomena. There are many more processes and functions that occur within the eye, contributing to our visual perception and overall eye health.

Optical coherence tomography (OCT) is a non-invasive imaging technique that uses low-coherence light to capture high-resolution cross-sectional images of biological tissues, particularly the retina and other ocular structures. OCT works by measuring the echo time delay of light scattered back from different depths within the tissue, creating a detailed map of the tissue's structure. This technique is widely used in ophthalmology to diagnose and monitor various eye conditions such as macular degeneration, diabetic retinopathy, and glaucoma.

The cornea is the clear, dome-shaped surface at the front of the eye. It plays a crucial role in focusing vision. The cornea protects the eye from harmful particles and microorganisms, and it also serves as a barrier against UV light. Its transparency allows light to pass through and get focused onto the retina. The cornea does not contain blood vessels, so it relies on tears and the fluid inside the eye (aqueous humor) for nutrition and oxygen. Any damage or disease that affects its clarity and shape can significantly impact vision and potentially lead to blindness if left untreated.

Intraocular pressure (IOP) is the fluid pressure within the eye, specifically within the anterior chamber, which is the space between the cornea and the iris. It is measured in millimeters of mercury (mmHg). The aqueous humor, a clear fluid that fills the anterior chamber, is constantly produced and drained, maintaining a balance that determines the IOP. Normal IOP ranges from 10-21 mmHg, with average values around 15-16 mmHg. Elevated IOP is a key risk factor for glaucoma, a group of eye conditions that can lead to optic nerve damage and vision loss if not treated promptly and effectively. Regular monitoring of IOP is essential in diagnosing and managing glaucoma and other ocular health issues.

The choroid is a layer of the eye that contains blood vessels that supply oxygen and nutrients to the outer layers of the retina. It lies between the sclera (the white, protective coat of the eye) and the retina (the light-sensitive tissue at the back of the eye). The choroid is essential for maintaining the health and function of the retina, particularly the photoreceptor cells that detect light and transmit visual signals to the brain. Damage to the choroid can lead to vision loss or impairment.

Intraocular lenses (IOLs) are artificial lens implants that are placed inside the eye during ophthalmic surgery, such as cataract removal. These lenses are designed to replace the natural lens of the eye that has become clouded or damaged, thereby restoring vision impairment caused by cataracts or other conditions.

There are several types of intraocular lenses available, including monofocal, multifocal, toric, and accommodative lenses. Monofocal IOLs provide clear vision at a single fixed distance, while multifocal IOLs offer clear vision at multiple distances. Toric IOLs are designed to correct astigmatism, and accommodative IOLs can change shape and position within the eye to allow for a range of vision.

The selection of the appropriate type of intraocular lens depends on various factors, including the patient's individual visual needs, lifestyle, and ocular health. The implantation procedure is typically performed on an outpatient basis and involves minimal discomfort or recovery time. Overall, intraocular lenses have become a safe and effective treatment option for patients with vision impairment due to cataracts or other eye conditions.

Ocular tonometry is a medical test used to measure the pressure inside the eye, also known as intraocular pressure (IOP). This test is an essential part of diagnosing and monitoring glaucoma, a group of eye conditions that can cause vision loss and blindness due to damage to the optic nerve from high IOP.

The most common method of ocular tonometry involves using a tonometer device that gently touches the front surface of the eye (cornea) with a small probe or prism. The device measures the amount of force required to flatten the cornea slightly, which correlates with the pressure inside the eye. Other methods of ocular tonometry include applanation tonometry, which uses a small amount of fluorescein dye and a blue light to measure the IOP, and rebound tonometry, which uses a lightweight probe that briefly touches the cornea and then bounces back to determine the IOP.

Regular ocular tonometry is important for detecting glaucoma early and preventing vision loss. It is typically performed during routine eye exams and may be recommended more frequently for individuals at higher risk of developing glaucoma, such as those with a family history of the condition or certain medical conditions like diabetes.

Aphakia is a medical condition that refers to the absence of the lens in the eye. This can occur naturally, but it's most commonly the result of surgery to remove a cataract, a cloudy lens that can cause vision loss. In some cases, the lens may not be successfully removed or may be accidentally lost during surgery, leading to aphakia. People with aphakia typically have significant vision problems and may require corrective measures such as glasses, contact lenses, or an intraocular lens implant to improve their vision.

Degenerative Myopia is a progressive form of nearsightedness, characterized by excessive elongation of the eyeball, which results in a steep curvature of the cornea and an overly long axial length. This condition causes light to focus in front of the retina instead of directly on it, resulting in blurred distance vision.

In degenerative myopia, this elongation continues throughout adulthood and is often associated with various complications such as thinning of the retinal tissue, stretching of the layers beneath the retina, and abnormal blood vessel growth. These changes can lead to a higher risk of developing retinal detachment, macular holes, glaucoma, and cataracts.

Degenerative myopia is considered a more severe form of myopia than the common or simple myopia, which usually stabilizes in the teenage years. It is also sometimes referred to as pathological myopia or malignant myopia. Regular eye examinations are essential for individuals with degenerative myopia to monitor and manage any potential complications.

Eyeglasses are a medical device used to correct vision problems. Also known as spectacles, they consist of frames that hold one or more lenses through which a person looks to see clearly. The lenses may be made of glass or plastic and are designed to compensate for various visual impairments such as nearsightedness, farsightedness, astigmatism, or presbyopia. Eyeglasses can be custom-made to fit an individual's face and prescription, and they come in a variety of styles, colors, and materials. Some people wear eyeglasses all the time, while others may only need to wear them for certain activities such as reading or driving.

The crystalline lens is a biconvex transparent structure in the eye that helps to refract (bend) light rays and focus them onto the retina. It is located behind the iris and pupil and is suspended by small fibers called zonules that connect it to the ciliary body. The lens can change its shape to accommodate and focus on objects at different distances, a process known as accommodation. With age, the lens may become cloudy or opaque, leading to cataracts.

Visual acuity is a measure of the sharpness or clarity of vision. It is usually tested by reading an eye chart from a specific distance, such as 20 feet (6 meters). The standard eye chart used for this purpose is called the Snellen chart, which contains rows of letters that decrease in size as you read down the chart.

Visual acuity is typically expressed as a fraction, with the numerator representing the testing distance and the denominator indicating the smallest line of type that can be read clearly. For example, if a person can read the line on the eye chart that corresponds to a visual acuity of 20/20, it means they have normal vision at 20 feet. If their visual acuity is 20/40, it means they must be as close as 20 feet to see what someone with normal vision can see at 40 feet.

It's important to note that visual acuity is just one aspect of overall vision and does not necessarily reflect other important factors such as peripheral vision, depth perception, color vision, or contrast sensitivity.

Corneal topography is a non-invasive medical imaging technique used to create a detailed map of the surface curvature of the cornea, which is the clear, dome-shaped surface at the front of the eye. This procedure provides valuable information about the shape and condition of the cornea, helping eye care professionals assess various eye conditions such as astigmatism, keratoconus, and other corneal abnormalities. It can also be used in contact lens fitting, refractive surgery planning, and post-surgical evaluation.

Angle-closure glaucoma is a type of glaucoma that is characterized by the sudden or gradually increasing pressure in the eye (intraocular pressure) due to the closure or narrowing of the angle between the iris and cornea. This angle is where the drainage system of the eye, called the trabecular meshwork, is located. When the angle becomes too narrow or closes completely, fluid cannot properly drain from the eye, leading to a buildup of pressure that can damage the optic nerve and cause permanent vision loss.

Angle-closure glaucoma can be either acute or chronic. Acute angle-closure glaucoma is a medical emergency that requires immediate treatment to prevent permanent vision loss. It is characterized by sudden symptoms such as severe eye pain, nausea and vomiting, blurred vision, halos around lights, and redness of the eye.

Chronic angle-closure glaucoma, on the other hand, develops more slowly over time and may not have any noticeable symptoms until significant damage has already occurred. It is important to diagnose and treat angle-closure glaucoma as early as possible to prevent vision loss. Treatment options include medications to lower eye pressure, laser treatment to create a new opening for fluid drainage, or surgery to improve the flow of fluid out of the eye.

The optic disk, also known as the optic nerve head, is the point where the optic nerve fibers exit the eye and transmit visual information to the brain. It appears as a pale, circular area in the back of the eye, near the center of the retina. The optic disk has no photoreceptor cells (rods and cones), so it is insensitive to light. It is an important structure to observe during eye examinations because changes in its appearance can indicate various ocular diseases or conditions, such as glaucoma, optic neuritis, or papilledema.

Eye diseases are a range of conditions that affect the eye or visual system, causing damage to vision and, in some cases, leading to blindness. These diseases can be categorized into various types, including:

1. Refractive errors: These include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, which affect the way light is focused on the retina and can usually be corrected with glasses or contact lenses.
2. Cataracts: A clouding of the lens inside the eye that leads to blurry vision, glare, and decreased contrast sensitivity. Cataract surgery is the most common treatment for this condition.
3. Glaucoma: A group of diseases characterized by increased pressure in the eye, leading to damage to the optic nerve and potential blindness if left untreated. Treatment includes medications, laser therapy, or surgery.
4. Age-related macular degeneration (AMD): A progressive condition that affects the central part of the retina called the macula, causing blurry vision and, in advanced stages, loss of central vision. Treatment may include anti-VEGF injections, laser therapy, or nutritional supplements.
5. Diabetic retinopathy: A complication of diabetes that affects the blood vessels in the retina, leading to bleeding, leakage, and potential blindness if left untreated. Treatment includes laser therapy, anti-VEGF injections, or surgery.
6. Retinal detachment: A separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly with surgery.
7. Amblyopia (lazy eye): A condition where one eye does not develop normal vision, often due to a misalignment or refractive error in childhood. Treatment includes correcting the underlying problem and encouraging the use of the weaker eye through patching or other methods.
8. Strabismus (crossed eyes): A misalignment of the eyes that can lead to amblyopia if not treated promptly with surgery, glasses, or other methods.
9. Corneal diseases: Conditions that affect the transparent outer layer of the eye, such as keratoconus, Fuchs' dystrophy, and infectious keratitis, which can lead to vision loss if not treated promptly.
10. Uveitis: Inflammation of the middle layer of the eye, which can cause vision loss if not treated promptly with anti-inflammatory medications or surgery.

Intraocular lens (IOL) implantation is a surgical procedure that involves placing a small artificial lens inside the eye to replace the natural lens that has been removed. This procedure is typically performed during cataract surgery, where the cloudy natural lens is removed and replaced with an IOL to restore clear vision.

During the procedure, a small incision is made in the eye, and the cloudy lens is broken up and removed using ultrasound waves or laser energy. Then, the folded IOL is inserted through the same incision and positioned in the correct place inside the eye. Once in place, the IOL unfolds and is secured into position.

There are several types of IOLs available, including monofocal, multifocal, toric, and accommodating lenses. Monofocal lenses provide clear vision at one distance, while multifocal lenses offer clear vision at multiple distances. Toric lenses correct astigmatism, and accommodating lenses can change shape to focus on objects at different distances.

Overall, intraocular lens implantation is a safe and effective procedure that can help restore clear vision in patients with cataracts or other eye conditions that require the removal of the natural lens.

Sensory deprivation, also known as perceptual isolation or sensory restriction, refers to the deliberate reduction or removal of stimuli from one or more of the senses. This can include limiting input from sight, sound, touch, taste, and smell. The goal is to limit a person's sensory experiences in order to study the effects on cognition, perception, and behavior.

In a clinical context, sensory deprivation can occur as a result of certain medical conditions or treatments, such as blindness, deafness, or pharmacological interventions that affect sensory processing. Prolonged sensory deprivation can lead to significant psychological and physiological effects, including hallucinations, delusions, and decreased cognitive function.

It's important to note that sensory deprivation should not be confused with meditation or relaxation techniques that involve reducing external stimuli in a controlled manner to promote relaxation and focus.

Diagnostic techniques in ophthalmology refer to the various methods and tests used by eye specialists (ophthalmologists) to examine, evaluate, and diagnose conditions related to the eyes and visual system. Here are some commonly used diagnostic techniques:

1. Visual Acuity Testing: This is a basic test to measure the sharpness of a person's vision. It typically involves reading letters or numbers from an eye chart at a specific distance.
2. Refraction Test: This test helps determine the correct lens prescription for glasses or contact lenses by measuring how light is bent as it passes through the cornea and lens.
3. Slit Lamp Examination: A slit lamp is a microscope that allows an ophthalmologist to examine the structures of the eye, including the cornea, iris, lens, and retina, in great detail.
4. Tonometry: This test measures the pressure inside the eye (intraocular pressure) to detect conditions like glaucoma. Common methods include applanation tonometry and non-contact tonometry.
5. Retinal Imaging: Several techniques are used to capture images of the retina, including fundus photography, fluorescein angiography, and optical coherence tomography (OCT). These tests help diagnose conditions like macular degeneration, diabetic retinopathy, and retinal detachments.
6. Color Vision Testing: This test evaluates a person's ability to distinguish between different colors, which can help detect color vision deficiencies or neurological disorders affecting the visual pathway.
7. Visual Field Testing: This test measures a person's peripheral (or side) vision and can help diagnose conditions like glaucoma, optic nerve damage, or brain injuries.
8. Pupillary Reactions Tests: These tests evaluate how the pupils respond to light and near objects, which can provide information about the condition of the eye's internal structures and the nervous system.
9. Ocular Motility Testing: This test assesses eye movements and alignment, helping diagnose conditions like strabismus (crossed eyes) or nystagmus (involuntary eye movement).
10. Corneal Topography: This non-invasive imaging technique maps the curvature of the cornea, which can help detect irregularities, assess the fit of contact lenses, and plan refractive surgery procedures.

Retinoscopy is a diagnostic technique used in optometry and ophthalmology to estimate the refractive error of the eye, or in other words, to determine the prescription for eyeglasses or contact lenses. This procedure involves shining a light into the patient's pupil and observing the reflection off the retina while introducing different lenses in front of the patient's eye. The examiner then uses specific movements and observations to determine the amount and type of refractive error, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, or presbyopia. Retinoscopy is a fundamental skill for eye care professionals and helps ensure that patients receive accurate prescriptions for corrective lenses.

Eye movements, also known as ocular motility, refer to the voluntary or involuntary motion of the eyes that allows for visual exploration of our environment. There are several types of eye movements, including:

1. Saccades: rapid, ballistic movements that quickly shift the gaze from one point to another.
2. Pursuits: smooth, slow movements that allow the eyes to follow a moving object.
3. Vergences: coordinated movements of both eyes in opposite directions, usually in response to a three-dimensional stimulus.
4. Vestibulo-ocular reflex (VOR): automatic eye movements that help stabilize the gaze during head movement.
5. Optokinetic nystagmus (OKN): rhythmic eye movements that occur in response to large moving visual patterns, such as when looking out of a moving vehicle.

Abnormalities in eye movements can indicate neurological or ophthalmological disorders and are often assessed during clinical examinations.

Scleral diseases refer to conditions that affect the sclera, which is the tough, white outer coating of the eye. The sclera helps to maintain the shape of the eye and provides protection for the internal structures. Scleral diseases can cause inflammation, degeneration, or thinning of the sclera, leading to potential vision loss or other complications. Some examples of scleral diseases include:

1. Scleritis: an inflammatory condition that causes pain, redness, and sensitivity in the affected area of the sclera. It can be associated with autoimmune disorders, infections, or trauma.
2. Episcleritis: a less severe form of inflammation that affects only the episclera, a thin layer of tissue overlying the sclera. Symptoms include redness and mild discomfort but typically no pain.
3. Pinguecula: a yellowish, raised deposit of protein and fat that forms on the conjunctiva, the clear membrane covering the sclera. While not a disease itself, a pinguecula can cause irritation or discomfort and may progress to a more severe condition called a pterygium.
4. Pterygium: a fleshy growth that extends from the conjunctiva onto the cornea, potentially obstructing vision. It is often associated with prolonged sun exposure and can be removed surgically if it becomes problematic.
5. Scleral thinning or melting: a rare but serious condition where the sclera degenerates or liquefies, leading to potential perforation of the eye. This can occur due to autoimmune disorders, infections, or as a complication of certain surgical procedures.
6. Ocular histoplasmosis syndrome (OHS): a condition caused by the Histoplasma capsulatum fungus, which can lead to scarring and vision loss if it involves the macula, the central part of the retina responsible for sharp, detailed vision.

It is essential to consult an ophthalmologist or eye care professional if you experience any symptoms related to scleral diseases to receive proper diagnosis and treatment.

The vitreous body, also known simply as the vitreous, is the clear, gel-like substance that fills the space between the lens and the retina in the eye. It is composed mainly of water, but also contains collagen fibers, hyaluronic acid, and other proteins. The vitreous helps to maintain the shape of the eye and provides a transparent medium for light to pass through to reach the retina. With age, the vitreous can become more liquefied and may eventually separate from the retina, leading to symptoms such as floaters or flashes of light.

Cataract extraction is a surgical procedure that involves removing the cloudy lens (cataract) from the eye. This procedure is typically performed to restore vision impairment caused by cataracts and improve overall quality of life. There are two primary methods for cataract extraction:

1. Phacoemulsification: This is the most common method used today. It involves making a small incision in the front part of the eye (cornea), inserting an ultrasonic probe to break up the cloudy lens into tiny pieces, and then removing those pieces with suction. After removing the cataract, an artificial intraocular lens (IOL) is inserted to replace the natural lens and help focus light onto the retina.

2. Extracapsular Cataract Extraction: In this method, a larger incision is made on the side of the cornea, allowing the surgeon to remove the cloudy lens in one piece without breaking it up. The back part of the lens capsule is left intact to support the IOL. This technique is less common and typically reserved for more advanced cataracts or when phacoemulsification cannot be performed.

Recovery from cataract extraction usually involves using eye drops to prevent infection and inflammation, as well as protecting the eye with a shield or glasses during sleep for a few weeks after surgery. Most people experience improved vision within a few days to a week following the procedure.

A cataract is a clouding of the natural lens in the eye that affects vision. This clouding can cause vision to become blurry, faded, or dim, making it difficult to see clearly. Cataracts are a common age-related condition, but they can also be caused by injury, disease, or medication use. In most cases, cataracts develop gradually over time and can be treated with surgery to remove the cloudy lens and replace it with an artificial one.

Optometry is a healthcare profession that involves examining, diagnosing, and treating disorders related to vision. Optometrists are the primary healthcare practitioners who specialize in prescribing and fitting eyeglasses and contact lenses to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia. They also diagnose and manage various eye diseases, including glaucoma, cataracts, and age-related macular degeneration. Optometrists may provide low vision care services to individuals with visual impairments and can offer pre- and post-operative care for patients undergoing eye surgery.

Optometry is a regulated profession that requires extensive education and training, including the completion of a Doctor of Optometry (O.D.) degree program and passing national and state licensing exams. In some jurisdictions, optometrists may also prescribe certain medications to treat eye conditions and diseases.

Silicone oils are synthetic, polymerized forms of siloxane, which is a type of silicon-based compound. These oils are known for their stability, durability, and resistance to heat, chemicals, and aging. In the medical field, silicone oils are often used in various medical devices and procedures, such as:

1. Intraocular lenses: Silicone oils can be used as a temporary replacement for the vitreous humor (the gel-like substance that fills the eye) during vitreoretinal surgery, particularly when there is a retinal detachment or other serious eye conditions. The oil helps to reattach the retina and maintain its position until a permanent solution can be found.

2. Breast implants: Silicone oils are used as a filling material for breast implants due to their ability to mimic the feel of natural breast tissue. However, the use of silicone breast implants has been controversial due to concerns about potential health risks, including immune system disorders and cancer.

3. Drug delivery systems: Silicone oils can be used as a component in drug-eluting devices, which are designed to deliver medication slowly and consistently over an extended period. These devices can be used in various medical applications, such as wound healing or the treatment of chronic pain.

4. Medical adhesives: Silicone oils can be incorporated into medical adhesives to improve their flexibility, biocompatibility, and resistance to moisture and heat. These adhesives are often used in the manufacturing of medical devices and for securing bandages or dressings to the skin.

It is important to note that while silicone oils have many medical applications, they can also pose potential risks, such as migration, inflammation, or other complications. Therefore, their use should be carefully considered and monitored by healthcare professionals.

Glaucoma is a group of eye conditions that damage the optic nerve, often caused by an abnormally high pressure in the eye (intraocular pressure). This damage can lead to permanent vision loss or even blindness if left untreated. The most common type is open-angle glaucoma, which has no warning signs and progresses slowly. Angle-closure glaucoma, on the other hand, can cause sudden eye pain, redness, nausea, and vomiting, as well as rapid vision loss. Other less common types of glaucoma also exist. While there is no cure for glaucoma, early detection and treatment can help slow or prevent further vision loss.

The macula lutea, often simply referred to as the macula or fovea centralis, is a part of the eye that is responsible for central vision and color perception. It's located in the center of the retina, the light-sensitive tissue at the back of the eye. The macula contains a high concentration of pigments called xanthophylls, which give it a yellowish color and protect the photoreceptor cells in this area from damage by blue light.

The central part of the macula is called the fovea, which is a small depression that contains only cones, the photoreceptor cells responsible for color vision and high visual acuity. The fovea is surrounded by the parafovea and the perifovea, which contain both cones and rods, the photoreceptor cells responsible for low-light vision and peripheral vision.

Damage to the macula can result in a loss of central vision and color perception, a condition known as age-related macular degeneration (AMD), which is a leading cause of blindness in older adults. Other conditions that can affect the macula include macular edema, macular holes, and macular pucker.

Anisometropia is a medical term that refers to a condition where there is a significant difference in the refractive power between the two eyes. In other words, one eye has a significantly different optical prescription compared to the other eye. This condition can cause issues with binocular vision and depth perception, and can sometimes lead to amblyopia (lazy eye) if not corrected early in life. It is typically diagnosed through a comprehensive eye examination and can be corrected with glasses or contact lenses.

Ocular accommodation is the process by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies. This is primarily achieved by the lens of the eye changing shape through the action of the ciliary muscles inside the eye. When you look at something far away, the lens becomes flatter, and when you look at something close up, the lens thickens. This ability to adjust focus allows for clear vision at different distances.

I'm sorry for any confusion, but "Singapore" is not a medical term or concept. It is a sovereign city-state and island country in Southeast Asia. If you have any questions related to medical topics or definitions, I would be happy to try and help answer those for you!

Phacoemulsification is a surgical procedure used in cataract removal. It involves using an ultrasonic device to emulsify (break up) the cloudy lens (cataract) into small pieces, which are then aspirated or sucked out through a small incision. This procedure allows for smaller incisions and faster recovery times compared to traditional cataract surgery methods. After the cataract is removed, an artificial intraocular lens (IOL) is typically implanted to replace the natural lens and restore vision.

I'm sorry for any confusion, but "Optics and Photonics" is a broad field that encompasses various scientific and engineering disciplines. It doesn't have a specific medical definition, as it's not a term typically used in a medical context.

However, I can provide a general definition:

Optics is the study of light and its interactions with matter. This includes how light is produced, controlled, transmitted, and detected. It involves phenomena such as reflection, refraction, diffraction, and interference.

Photonics, on the other hand, is a branch of optics that deals with the generation, detection, and manipulation of individual photons, the basic units of light. Photonics is often applied to technologies such as lasers, fiber optics, and optical communications.

In a medical context, these fields might be used in various diagnostic and therapeutic applications, such as endoscopes, ophthalmic devices, laser surgery, and imaging technologies like MRI and CT scans. But the terms "Optics" and "Photonics" themselves are not medical conditions or treatments.

Eye abnormalities refer to any structural or functional anomalies that affect the eye or its surrounding tissues. These abnormalities can be present at birth (congenital) or acquired later in life due to various factors such as injury, disease, or aging. Some examples of eye abnormalities include:

1. Strabismus: Also known as crossed eyes, strabismus is a condition where the eyes are misaligned and point in different directions.
2. Nystagmus: This is an involuntary movement of the eyes that can be horizontal, vertical, or rotatory.
3. Cataracts: A cataract is a clouding of the lens inside the eye that can cause vision loss.
4. Glaucoma: This is a group of eye conditions that damage the optic nerve and can lead to vision loss.
5. Retinal disorders: These include conditions such as retinal detachment, macular degeneration, and diabetic retinopathy.
6. Corneal abnormalities: These include conditions such as keratoconus, corneal ulcers, and Fuchs' dystrophy.
7. Orbital abnormalities: These include conditions such as orbital tumors, thyroid eye disease, and Graves' ophthalmopathy.
8. Ptosis: This is a condition where the upper eyelid droops over the eye.
9. Color blindness: A condition where a person has difficulty distinguishing between certain colors.
10. Microphthalmia: A condition where one or both eyes are abnormally small.

These are just a few examples of eye abnormalities, and there are many others that can affect the eye and its functioning. If you suspect that you have an eye abnormality, it is important to consult with an ophthalmologist for proper diagnosis and treatment.

Eye color is a characteristic determined by variations in a person's genes. The color of the eyes depends on the amount and type of pigment called melanin found in the eye's iris.

There are three main types of eye colors: brown, blue, and green. Brown eyes have the most melanin, while blue eyes have the least. Green eyes have a moderate amount of melanin combined with a golden tint that reflects light to give them their unique color.

Eye color is a polygenic trait, which means it is influenced by multiple genes. The two main genes responsible for eye color are OCA2 and HERC2, both located on chromosome 15. These genes control the production, transport, and storage of melanin in the iris.

It's important to note that eye color can change during infancy and early childhood due to the development of melanin in the iris. Additionally, some medications or medical conditions may also cause changes in eye color over time.

Microphthalmos is a medical condition where one or both eyes are abnormally small due to developmental anomalies in the eye. The size of the eye may vary from slightly smaller than normal to barely visible. This condition can occur in isolation or as part of a syndrome with other congenital abnormalities. It can also be associated with other ocular conditions such as cataracts, retinal disorders, and orbital defects. Depending on the severity, microphthalmos may lead to visual impairment or blindness.

Ophthalmoscopy is a medical examination technique used by healthcare professionals to observe the interior structures of the eye, including the retina, optic disc, and vitreous humor. This procedure typically involves using an ophthalmoscope, a handheld device that consists of a light and magnifying lenses. The healthcare provider looks through the ophthalmoscope and directly observes the internal structures of the eye by illuminating them.

There are several types of ophthalmoscopy, including direct ophthalmoscopy, indirect ophthalmoscopy, and slit-lamp biomicroscopy. Each type has its own advantages and disadvantages, and they may be used in different situations depending on the specific clinical situation and the information needed.

Ophthalmoscopy is an important diagnostic tool for detecting and monitoring a wide range of eye conditions, including diabetic retinopathy, glaucoma, age-related macular degeneration, and other retinal disorders. It can also provide valuable information about the overall health of the individual, as changes in the appearance of the retina or optic nerve may indicate the presence of systemic diseases such as hypertension or diabetes.

The posterior segment of the eye refers to the back portion of the interior of the eye, including the vitreous, retina, choroid, and optic nerve. This region is responsible for processing visual information and transmitting it to the brain. The retina contains photoreceptor cells that convert light into electrical signals, which are then sent through the optic nerve to the brain for interpretation as images. Disorders of the posterior eye segment can lead to vision loss or blindness.

"Length of Stay" (LOS) is a term commonly used in healthcare to refer to the amount of time a patient spends receiving care in a hospital, clinic, or other healthcare facility. It is typically measured in hours, days, or weeks and can be used as a metric for various purposes such as resource planning, quality assessment, and reimbursement. The length of stay can vary depending on the type of illness or injury, the severity of the condition, the patient's response to treatment, and other factors. It is an important consideration in healthcare management and can have significant implications for both patients and providers.

Astigmatism is a common eye condition that occurs when the cornea or lens has an irregular shape, causing blurred or distorted vision. The cornea and lens are typically smooth and curved uniformly in all directions, allowing light to focus clearly on the retina. However, if the cornea or lens is not smoothly curved and has a steeper curve in one direction than the other, it causes light to focus unevenly on the retina, leading to astigmatism.

Astigmatism can cause blurred vision at all distances, as well as eye strain, headaches, and fatigue. It is often present from birth and can be hereditary, but it can also develop later in life due to eye injuries or surgery. Astigmatism can be corrected with glasses, contact lenses, or refractive surgery such as LASIK.

A pupil, in medical terms, refers to the circular opening in the center of the iris (the colored part of the eye) that allows light to enter and reach the retina. The size of the pupil can change involuntarily in response to light intensity and emotional state, as well as voluntarily through certain eye exercises or with the use of eye drops. Pupillary reactions are important in clinical examinations as they can provide valuable information about the nervous system's functioning, particularly the brainstem and cranial nerves II and III.

Eye injuries refer to any damage or trauma caused to the eye or its surrounding structures. These injuries can vary in severity and may include:

1. Corneal abrasions: A scratch or scrape on the clear surface of the eye (cornea).
2. Chemical burns: Occurs when chemicals come into contact with the eye, causing damage to the cornea and other structures.
3. Eyelid lacerations: Cuts or tears to the eyelid.
4. Subconjunctival hemorrhage: Bleeding under the conjunctiva, the clear membrane that covers the white part of the eye.
5. Hyphema: Accumulation of blood in the anterior chamber of the eye, which is the space between the cornea and iris.
6. Orbital fractures: Breaks in the bones surrounding the eye.
7. Retinal detachment: Separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly.
8. Traumatic uveitis: Inflammation of the uvea, the middle layer of the eye, caused by trauma.
9. Optic nerve damage: Damage to the optic nerve, which transmits visual information from the eye to the brain.

Eye injuries can result from a variety of causes, including accidents, sports-related injuries, violence, and chemical exposure. It is important to seek medical attention promptly for any suspected eye injury to prevent further damage and potential vision loss.

Genetic determinism is a philosophical concept that suggests that our genetic makeup is the sole determining factor for our traits, behaviors, and diseases. According to this perspective, our genes dictate our development, personality, health outcomes, and other aspects of our lives, with little or no influence from environmental factors or personal choices.

However, this view has been largely discredited by modern genetic research, which has shown that the relationship between genes and traits is much more complex than previously thought. Most traits are influenced by a combination of multiple genes (known as polygenic inheritance) and environmental factors, making it difficult to predict outcomes based solely on genetics.

It's important to note that while our genes can influence our risk for certain diseases or conditions, they do not determine our destiny. Lifestyle choices, environment, and other factors can also play a significant role in shaping our health and well-being.

Mydriatics are medications that cause mydriasis, which is the dilation of the pupil. These drugs work by blocking the action of the muscarinic receptors in the iris, leading to relaxation of the circular muscle and constriction of the radial muscle, resulting in pupil dilation. Mydriatics are often used in eye examinations to facilitate examination of the interior structures of the eye. Commonly used mydriatic agents include tropicamide, phenylephrine, and cyclopentolate. It is important to note that mydriatics can have side effects such as blurred vision, photophobia, and accommodation difficulties, so patients should be advised accordingly.

The retina is the innermost, light-sensitive layer of tissue in the eye of many vertebrates and some cephalopods. It receives light that has been focused by the cornea and lens, converts it into neural signals, and sends these to the brain via the optic nerve. The retina contains several types of photoreceptor cells including rods (which handle vision in low light) and cones (which are active in bright light and are capable of color vision).

In medical terms, any pathological changes or diseases affecting the retinal structure and function can lead to visual impairment or blindness. Examples include age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinitis pigmentosa among others.

The term "Asian Continental Ancestry Group" is a medical/ethnic classification used to describe a person's genetic background and ancestry. According to this categorization, individuals with origins in the Asian continent are grouped together. This includes populations from regions such as East Asia (e.g., China, Japan, Korea), South Asia (e.g., India, Pakistan, Bangladesh), Southeast Asia (e.g., Philippines, Indonesia, Thailand), and Central Asia (e.g., Kazakhstan, Uzbekistan, Tajikistan). It is important to note that this broad categorization may not fully capture the genetic diversity within these regions or accurately reflect an individual's specific ancestral origins.

Pseudophakia is a medical term that refers to the condition where a person's natural lens in the eye has been replaced with an artificial one. This procedure is typically performed during cataract surgery, where the cloudy, natural lens is removed and replaced with a clear, artificial lens to improve vision. The prefix "pseudo" means false or fake, and "phakia" refers to the natural lens of the eye, hence the term "Pseudophakia" implies a false or artificial lens.

Nerve fibers are specialized structures that constitute the long, slender processes (axons) of neurons (nerve cells). They are responsible for conducting electrical impulses, known as action potentials, away from the cell body and transmitting them to other neurons or effector organs such as muscles and glands. Nerve fibers are often surrounded by supportive cells called glial cells and are grouped together to form nerve bundles or nerves. These fibers can be myelinated (covered with a fatty insulating sheath called myelin) or unmyelinated, which influences the speed of impulse transmission.

Acoustic microscopy is a non-invasive imaging technique that uses sound waves to visualize and analyze the structure and properties of various materials, including biological samples. In the context of medical diagnostics and research, acoustic microscopy can be used to examine tissues, cells, and cellular components with high resolution, providing valuable information about their mechanical and physical properties.

In acoustic microscopy, high-frequency sound waves are focused onto a sample using a transducer. The interaction between the sound waves and the sample generates echoes, which contain information about the sample's internal structure and properties. These echoes are then recorded and processed to create an image of the sample.

Acoustic microscopy offers several advantages over other imaging techniques, such as optical microscopy or electron microscopy. For example, it does not require staining or labeling of samples, which can be time-consuming and potentially damaging. Additionally, acoustic microscopy can provide high-resolution images of samples in their native state, allowing researchers to study the effects of various treatments or interventions on living cells and tissues.

In summary, acoustic microscopy is a non-invasive imaging technique that uses sound waves to visualize and analyze the structure and properties of biological samples with high resolution, providing valuable information for medical diagnostics and research.

In the context of medical terminology, "lenses" generally refers to optical lenses used in various medical devices and instruments. These lenses are typically made of glass or plastic and are designed to refract (bend) light in specific ways to help magnify, focus, or redirect images. Here are some examples:

1. In ophthalmology and optometry, lenses are used in eyeglasses, contact lenses, and ophthalmic instruments to correct vision problems like myopia (nearsightedness), hypermetropia (farsightedness), astigmatism, or presbyopia.
2. In surgical microscopes, lenses are used to provide a magnified and clear view of the operating field during microsurgical procedures like ophthalmic, neurosurgical, or ENT (Ear, Nose, Throat) surgeries.
3. In endoscopes and laparoscopes, lenses are used to transmit light and images from inside the body during minimally invasive surgical procedures.
4. In ophthalmic diagnostic instruments like slit lamps, lenses are used to examine various structures of the eye in detail.

In summary, "lenses" in medical terminology refer to optical components that help manipulate light to aid in diagnosis, treatment, or visual correction.

Retinal Ganglion Cells (RGCs) are a type of neuron located in the innermost layer of the retina, the light-sensitive tissue at the back of the eye. These cells receive visual information from photoreceptors (rods and cones) via intermediate cells called bipolar cells. RGCs then send this visual information through their long axons to form the optic nerve, which transmits the signals to the brain for processing and interpretation as vision.

There are several types of RGCs, each with distinct morphological and functional characteristics. Some RGCs are specialized in detecting specific features of the visual scene, such as motion, contrast, color, or brightness. The diversity of RGCs allows for a rich and complex representation of the visual world in the brain.

Damage to RGCs can lead to various visual impairments, including loss of vision, reduced visual acuity, and altered visual fields. Conditions associated with RGC damage or degeneration include glaucoma, optic neuritis, ischemic optic neuropathy, and some inherited retinal diseases.

Axial length, in the context of the eye, refers to the measurement of the distance between the front and back portions of the eye, specifically from the cornea (the clear front "window" of the eye) to the retina (the light-sensitive tissue at the back of the eye). This measurement is typically expressed in millimeters (mm).

The axial length of the eye is an important factor in determining the overall refractive power of the eye and can play a role in the development of various eye conditions, such as myopia (nearsightedness) or hyperopia (farsightedness). Changes in axial length, particularly elongation, are often associated with an increased risk of developing myopia. Regular monitoring of axial length can help eye care professionals track changes in the eye and manage these conditions more effectively.

I'm sorry for any confusion, but "photography" is not a term typically used in medical definitions. Photography refers to the art, application, or process of creating images by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film.

If you're looking for a medical term related to imaging, there are several terms that might be relevant, such as:

1. Radiography: This is a technique using X-rays to visualize the internal structures of the body.
2. Ultrasonography: Also known as ultrasound, this is a diagnostic imaging technique using high-frequency sound waves to create images of the inside of the body.
3. Computed Tomography (CT): A type of imaging that uses X-rays to create detailed cross-sectional images of the body.
4. Magnetic Resonance Imaging (MRI): A type of imaging that uses magnetic fields and radio waves to create detailed images of the organs and tissues within the body.
5. Nuclear Medicine: This is a branch of medical imaging that uses small amounts of radioactive material to diagnose and treat diseases.

If you have any questions related to medical definitions or topics, feel free to ask!

Cyclopentolate is a medication that belongs to a class of drugs called anticholinergics. It is primarily used as an eye drop to dilate the pupils and prevent the muscles in the eye from focusing, which can help doctors to examine the back of the eye more thoroughly.

The medical definition of Cyclopentolate is:

A cycloplegic and mydriatic agent that is used topically to produce pupillary dilation and cyclospasm, and to paralyze accommodation. It is used in the diagnosis and treatment of various ocular conditions, including refractive errors, corneal injuries, and uveitis. The drug works by blocking the action of acetylcholine, a neurotransmitter that is involved in the regulation of pupil size and focus.

Cyclopentolate is available as an eye drop solution, typically at concentrations of 0.5% or 1%. It is usually administered one to two times, with the second dose given after about 5 to 10 minutes. The effects of the drug can last for several hours, depending on the dosage and individual patient factors.

While cyclopentolate is generally considered safe when used as directed, it can cause side effects such as stinging or burning upon instillation, blurred vision, photophobia (sensitivity to light), and dry mouth. In rare cases, more serious side effects such as confusion, agitation, or hallucinations may occur, particularly in children or older adults. It is important to follow the instructions of a healthcare provider when using cyclopentolate, and to report any unusual symptoms or side effects promptly.

Dry eye syndrome, also known as keratoconjunctivitis sicca, is a condition characterized by insufficient lubrication and moisture of the eyes. This occurs when the tears produced by the eyes are not sufficient in quantity or quality to keep the eyes moist and comfortable. The medical definition of dry eye syndromes includes the following symptoms:

1. A gritty or sandy sensation in the eyes
2. Burning or stinging sensations
3. Redness and irritation
4. Blurred vision that improves with blinking
5. Light sensitivity
6. A feeling of something foreign in the eye
7. Stringy mucus in or around the eyes
8. Difficulty wearing contact lenses
9. Watery eyes, which may seem contradictory but can be a response to dryness
10. Eye fatigue and discomfort after prolonged screen time or reading

The causes of dry eye syndromes can include aging, hormonal changes, certain medical conditions (such as diabetes, rheumatoid arthritis, lupus, Sjogren's syndrome), medications (antihistamines, decongestants, antidepressants, birth control pills), environmental factors (dry air, wind, smoke, dust), and prolonged screen time or reading.

Treatment for dry eye syndromes depends on the severity of the condition and its underlying causes. It may include artificial tears, lifestyle changes, prescription medications, and in some cases, surgical procedures to improve tear production or drainage.

Endotamponade is a medical term that refers to the use of an internal tamponade in ophthalmology, specifically in the treatment of certain eye conditions such as retinal detachment or severe ocular trauma.

In this procedure, a gas or liquid material is injected into the vitreous cavity (the space inside the eye between the lens and the retina) to help reattach the retina to the wall of the eye or to control bleeding inside the eye. The tamponading agent presses against the retina, holding it in place and preventing further fluid from accumulating under it, which can help promote healing and prevent further damage.

The choice of tamponade material depends on the specific condition being treated. For example, a gas bubble may be used for retinal detachment, while silicone oil may be used for more complex cases or where a longer-lasting tamponade is required. The gas or liquid is usually injected through a small incision in the eye and may be left in place for several weeks or months, depending on the individual case.

Overall, endotamponade is an important technique in the management of various retinal disorders and can help preserve vision and prevent blindness in certain cases.

The anterior eye segment refers to the front portion of the eye, which includes the cornea, iris, ciliary body, and lens. The cornea is the clear, dome-shaped surface at the front of the eye that refracts light entering the eye and provides protection. The iris is the colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil. The ciliary body is a muscle that changes the shape of the lens to focus on objects at different distances. The lens is a transparent structure located behind the iris that further refracts light to provide a clear image. Together, these structures work to focus light onto the retina and enable vision.

Gonioscopy is a diagnostic procedure in ophthalmology used to examine the anterior chamber angle, which is the area where the iris and cornea meet. This examination helps to evaluate the drainage pathways of the eye for conditions such as glaucoma. A special contact lens called a goniolens is placed on the cornea during the procedure to allow the healthcare provider to visualize the angle using a biomicroscope. The lens may be coupled with a mirrored or prismatic surface to enhance the view of the angle. Gonioscopy can help detect conditions like narrow angles, closed angles, neovascularization, and other abnormalities that might contribute to glaucoma development or progression.

Open-angle glaucoma is a chronic, progressive type of glaucoma characterized by the gradual loss of optic nerve fibers and resulting in visual field defects. It is called "open-angle" because the angle where the iris meets the cornea (trabecular meshwork) appears to be normal and open on examination. The exact cause of this condition is not fully understood, but it is associated with increased resistance to the outflow of aqueous humor within the trabecular meshwork, leading to an increase in intraocular pressure (IOP). This elevated IOP can cause damage to the optic nerve and result in vision loss.

The onset of open-angle glaucoma is often asymptomatic, making regular comprehensive eye examinations crucial for early detection and management. Treatment typically involves lowering IOP using medications, laser therapy, or surgery to prevent further optic nerve damage and preserve vision.

Retinal detachment is a serious eye condition that occurs when the retina, a thin layer of tissue at the back of the eye responsible for processing light and sending visual signals to the brain, pulls away from its normal position. This can lead to significant vision loss or even blindness if not promptly treated. Retinal detachment can be caused by various factors such as aging, trauma, eye disease, or an inflammatory condition. Symptoms of retinal detachment may include sudden flashes of light, floaters, a shadow in the peripheral vision, or a curtain-like covering over part of the visual field. Immediate medical attention is necessary to prevent further damage and preserve vision.

Monocular vision refers to the ability to see and process visual information using only one eye. It is the type of vision that an individual has when they are using only one eye to look at something, while the other eye may be covered or not functioning. This can be contrasted with binocular vision, which involves the use of both eyes working together to provide depth perception and a single, combined visual field.

Monocular vision is important for tasks that only require the use of one eye, such as when looking through a microscope or using a telescope. However, it does not provide the same level of depth perception and spatial awareness as binocular vision. In some cases, individuals may have reduced visual acuity or other visual impairments in one eye, leading to limited monocular vision in that eye. It is important for individuals with monocular vision to have regular eye exams to monitor their eye health and ensure that any visual impairments are detected and treated promptly.

Contact lenses are thin, curved plastic or silicone hydrogel devices that are placed on the eye to correct vision, replace a missing or damaged cornea, or for cosmetic purposes. They rest on the surface of the eye, called the cornea, and conform to its shape. Contact lenses are designed to float on a thin layer of tears and move with each blink.

There are two main types of contact lenses: soft and rigid gas permeable (RGP). Soft contact lenses are made of flexible hydrophilic (water-absorbing) materials that allow oxygen to pass through the lens to the cornea. RGP lenses are made of harder, more oxygen-permeable materials.

Contact lenses can be used to correct various vision problems, including nearsightedness, farsightedness, astigmatism, and presbyopia. They come in different shapes, sizes, and powers to suit individual needs and preferences. Proper care, handling, and regular check-ups with an eye care professional are essential for maintaining good eye health and preventing complications associated with contact lens wear.

"Tupaia" is not a term found in general medical terminology. It is most likely referring to a genus of small mammals known as tree shrews, also called "tupaias." They are native to Southeast Asia and are not closely related to shrews, but rather belong to their own order, Scandentia.

However, if you're referring to a specific medical condition or concept that uses the term "Tupaia," I would need more context to provide an accurate definition.

A vitrectomy is a surgical procedure that involves the removal of some or all of the vitreous humor, which is the clear gel-like substance filling the center of the eye. This surgery is often performed to treat various retinal disorders such as diabetic retinopathy, retinal detachment, macular hole, and vitreous hemorrhage.

During a vitrectomy, the ophthalmologist makes small incisions in the sclera (the white part of the eye) to access the vitreous cavity. The surgeon then uses specialized instruments to remove the cloudy or damaged vitreous and may also repair any damage to the retina or surrounding tissues. Afterward, a clear saline solution is injected into the eye to maintain its shape and help facilitate healing.

In some cases, a gas bubble or silicone oil may be placed in the eye after the vitrectomy to help hold the retina in place while it heals. These substances will gradually be absorbed or removed during follow-up appointments. The body naturally produces a new, clear vitreous to replace the removed material over time.

Vitrectomy is typically performed under local anesthesia and may require hospitalization or outpatient care depending on the individual case. Potential risks and complications include infection, bleeding, cataract formation, retinal detachment, and increased eye pressure. However, with proper care and follow-up, most patients experience improved vision after a successful vitrectomy procedure.

In medical terms, the iris refers to the colored portion of the eye that surrounds the pupil. It is a circular structure composed of thin, contractile muscle fibers (radial and circumferential) arranged in a regular pattern. These muscles are controlled by the autonomic nervous system and can adjust the size of the pupil in response to changes in light intensity or emotional arousal. By constricting or dilating the iris, the amount of light entering the eye can be regulated, which helps maintain optimal visual acuity under various lighting conditions.

The color of the iris is determined by the concentration and distribution of melanin pigments within the iris stroma. The iris also contains blood vessels, nerves, and connective tissue that support its structure and function. Anatomically, the iris is continuous with the ciliary body and the choroid, forming part of the uveal tract in the eye.

Anthropometry is the scientific study of measurements and proportions of the human body. It involves the systematic measurement and analysis of various physical characteristics, such as height, weight, blood pressure, waist circumference, and other body measurements. These measurements are used in a variety of fields, including medicine, ergonomics, forensics, and fashion design, to assess health status, fitness level, or to design products and environments that fit the human body. In a medical context, anthropometry is often used to assess growth and development, health status, and disease risk factors in individuals and populations.

Refractometry is a medical laboratory technique used to measure the refractive index of a substance, typically a liquid. The refractive index is the ratio of the speed of light in a vacuum to its speed in the substance being measured. In a clinical setting, refractometry is often used to determine the concentration of total solids in a fluid, such as urine or serum, by measuring the angle at which light passes through the sample. This information can be useful in the diagnosis and monitoring of various medical conditions, including dehydration, kidney disease, and diabetes. Refractometry is also used in the field of optometry to measure the refractive error of the eye, or the amount and type of correction needed to provide clear vision.

Ocular hypertension is a medical condition characterized by elevated pressure within the eye (intraocular pressure or IOP), which is higher than normal but not necessarily high enough to cause any visible damage to the optic nerve or visual field loss. It serves as a significant risk factor for developing glaucoma, a sight-threatening disease.

The normal range of intraocular pressure is typically between 10-21 mmHg (millimeters of mercury). Ocular hypertension is often defined as an IOP consistently above 21 mmHg, although some studies suggest that even pressures between 22-30 mmHg may not cause damage in all individuals. Regular monitoring and follow-up with an ophthalmologist are essential for people diagnosed with ocular hypertension to ensure early detection and management of any potential glaucomatous changes. Treatment options include medications, laser therapy, or surgery to lower the IOP and reduce the risk of glaucoma onset.

Corneal diseases are a group of disorders that affect the cornea, which is the clear, dome-shaped surface at the front of the eye. The cornea plays an important role in focusing vision, and any damage or disease can cause significant visual impairment or loss. Some common types of corneal diseases include:

1. Keratoconus: A progressive disorder in which the cornea thins and bulges outward into a cone shape, causing distorted vision.
2. Fuchs' dystrophy: A genetic disorder that affects the inner layer of the cornea called the endothelium, leading to swelling, cloudiness, and decreased vision.
3. Dry eye syndrome: A condition in which the eyes do not produce enough tears or the tears evaporate too quickly, causing discomfort, redness, and blurred vision.
4. Corneal ulcers: Open sores on the cornea that can be caused by infection, trauma, or other factors.
5. Herpes simplex keratitis: A viral infection of the cornea that can cause recurrent episodes of inflammation, scarring, and vision loss.
6. Corneal dystrophies: Inherited disorders that affect the structure and clarity of the cornea, leading to visual impairment or blindness.
7. Bullous keratopathy: A condition in which the endothelium fails to pump fluid out of the cornea, causing it to swell and form blisters.
8. Corneal trauma: Injury to the cornea caused by foreign objects, chemicals, or other factors that can lead to scarring, infection, and vision loss.

Treatment for corneal diseases varies depending on the specific condition and severity of the disease. Options may include eyedrops, medications, laser surgery, corneal transplantation, or other treatments.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

Aphakia, postcataract is a medical condition that refers to the absence of the lens in the eye after cataract surgery. A cataract is a clouding of the natural lens inside the eye that can cause vision loss. During cataract surgery, the cloudy lens is removed and replaced with an artificial lens implant. However, if there is a complication during the procedure and the artificial lens is not placed in the eye or if it becomes dislocated after surgery, then the patient will develop aphakia, postcataract.

Patients with aphakia, postcataract have poor vision and may experience symptoms such as blurry vision, glare, and halos around lights. They are also at an increased risk of developing glaucoma and retinal detachment. To correct the vision in patients with aphakia, they can wear special contact lenses or glasses with high-powered lenses, or undergo a secondary surgical procedure to implant an artificial lens in the eye.

Eye burns typically refer to injuries or damage to the eyes caused by exposure to harmful substances, extreme temperatures, or radiation. This can result in a variety of symptoms, including redness, pain, tearing, swelling, and blurred vision.

Chemical eye burns can occur when the eyes come into contact with strong acids, alkalis, or other irritants. These substances can cause damage to the cornea, conjunctiva, and other structures of the eye. The severity of the burn will depend on the type and concentration of the chemical, as well as the length of time it was in contact with the eye.

Thermal eye burns can result from exposure to hot or cold temperatures, such as steam, flames, or extreme cold. These types of burns can cause damage to the surface of the eye and may require medical attention to prevent further complications.

Radiation eye burns can occur after exposure to high levels of ultraviolet (UV) light, such as from welding torches, sun lamps, or tanning beds. Prolonged exposure to these sources can cause damage to the cornea and other structures of the eye, leading to symptoms like pain, redness, and sensitivity to light.

If you experience symptoms of an eye burn, it is important to seek medical attention as soon as possible. Treatment may include flushing the eyes with water or saline solution, administering medication to relieve pain and inflammation, or in severe cases, surgery to repair damaged tissue.

Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.

In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.

The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

The fovea centralis, also known as the macula lutea, is a small pit or depression located in the center of the retina, an light-sensitive tissue at the back of the eye. It is responsible for sharp, detailed vision (central vision) and color perception. The fovea contains only cones, the photoreceptor cells that are responsible for color vision and high visual acuity. It has a higher concentration of cones than any other area in the retina, allowing it to provide the greatest detail and color discrimination. The center of the fovea is called the foveola, which contains the highest density of cones and is avascular, meaning it lacks blood vessels to avoid interfering with the light passing through to the photoreceptor cells.

Cross-sectional anatomy refers to the study and visualization of the internal structures of the body as if they were cut along a plane, creating a two-dimensional image. This method allows for a detailed examination of the relationships between various organs, tissues, and structures that may not be as easily appreciated through traditional observation or examination.

In cross-sectional anatomy, different imaging techniques such as computed tomography (CT) scans, magnetic resonance imaging (MRI), and ultrasound are used to create detailed images of the body's internal structures at various depths and planes. These images can help medical professionals diagnose conditions, plan treatments, and assess the effectiveness of interventions.

Cross-sectional anatomy is an important tool in modern medicine, as it provides a more comprehensive understanding of the human body than traditional gross anatomy alone. By allowing for a detailed examination of the internal structures of the body, cross-sectional anatomy can help medical professionals make more informed decisions about patient care.

Hydrophilic contact lenses are a type of contact lens that is designed to absorb and retain water. These lenses are made from materials that have an affinity for water, which helps them to remain moist and comfortable on the eye. The water content of hydrophilic contact lenses can vary, but typically ranges from 30-80% by weight.

Hydrophilic contact lenses are often used to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. They can be made in a variety of materials, including soft hydrogel and silicone hydrogel.

One advantage of hydrophilic contact lenses is that they tend to be more comfortable to wear than other types of contacts, as they retain moisture and conform closely to the shape of the eye. However, they may also be more prone to deposits and buildup, which can lead to protein accumulation and discomfort over time. Proper care and cleaning are essential to maintain the health of the eyes when wearing hydrophilic contact lenses.

Aging is a complex, progressive and inevitable process of bodily changes over time, characterized by the accumulation of cellular damage and degenerative changes that eventually lead to increased vulnerability to disease and death. It involves various biological, genetic, environmental, and lifestyle factors that contribute to the decline in physical and mental functions. The medical field studies aging through the discipline of gerontology, which aims to understand the underlying mechanisms of aging and develop interventions to promote healthy aging and extend the human healthspan.

Restriction Fragment Length Polymorphism (RFLP) is a term used in molecular biology and genetics. It refers to the presence of variations in DNA sequences among individuals, which can be detected by restriction enzymes. These enzymes cut DNA at specific sites, creating fragments of different lengths.

In RFLP analysis, DNA is isolated from an individual and treated with a specific restriction enzyme that cuts the DNA at particular recognition sites. The resulting fragments are then separated by size using gel electrophoresis, creating a pattern unique to that individual's DNA. If there are variations in the DNA sequence between individuals, the restriction enzyme may cut the DNA at different sites, leading to differences in the length of the fragments and thus, a different pattern on the gel.

These variations can be used for various purposes, such as identifying individuals, diagnosing genetic diseases, or studying evolutionary relationships between species. However, RFLP analysis has largely been replaced by more modern techniques like polymerase chain reaction (PCR)-based methods and DNA sequencing, which offer higher resolution and throughput.

Eye enucleation is a surgical procedure that involves the removal of the entire eyeball, leaving the eye muscles, eyelids, and orbital structures intact. This procedure is typically performed to treat severe eye conditions or injuries, such as uncontrollable pain, blindness, cancer, or trauma. After the eyeball is removed, an implant may be placed in the socket to help maintain its shape and appearance. The optic nerve and other surrounding tissues are cut during the enucleation procedure, which means that vision cannot be restored in the affected eye. However, the remaining eye structures can still function normally, allowing for regular blinking, tear production, and eyelid movement.

A circadian rhythm is a roughly 24-hour biological cycle that regulates various physiological and behavioral processes in living organisms. It is driven by the body's internal clock, which is primarily located in the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain.

The circadian rhythm controls many aspects of human physiology, including sleep-wake cycles, hormone secretion, body temperature, and metabolism. It helps to synchronize these processes with the external environment, particularly the day-night cycle caused by the rotation of the Earth.

Disruptions to the circadian rhythm can have negative effects on health, leading to conditions such as insomnia, sleep disorders, depression, bipolar disorder, and even increased risk of chronic diseases like cancer, diabetes, and cardiovascular disease. Factors that can disrupt the circadian rhythm include shift work, jet lag, irregular sleep schedules, and exposure to artificial light at night.

Retrospective studies, also known as retrospective research or looking back studies, are a type of observational study that examines data from the past to draw conclusions about possible causal relationships between risk factors and outcomes. In these studies, researchers analyze existing records, medical charts, or previously collected data to test a hypothesis or answer a specific research question.

Retrospective studies can be useful for generating hypotheses and identifying trends, but they have limitations compared to prospective studies, which follow participants forward in time from exposure to outcome. Retrospective studies are subject to biases such as recall bias, selection bias, and information bias, which can affect the validity of the results. Therefore, retrospective studies should be interpreted with caution and used primarily to generate hypotheses for further testing in prospective studies.

The Bruch membrane is a thin, layered structure that separates the retina from the choroid in the eye. It is composed of five layers: the basement membrane of the retinal pigment epithelium (RPE), the inner collagenous layer, the elastic layer, the outer collagenous layer, and the basement membrane of the choriocapillaris. The Bruch membrane provides structural support to the RPE and serves as a barrier between the retina and the choroid, allowing for the selective transport of nutrients and waste products. It also plays a role in maintaining the health of the photoreceptors in the retina. Damage to the Bruch membrane is associated with age-related macular degeneration (AMD), a leading cause of vision loss in older adults.

Retinopathy of Prematurity (ROP) is a potentially sight-threatening proliferative retinal vascular disorder that primarily affects prematurely born infants, particularly those with low birth weight and/or young gestational age. It is characterized by the abnormal growth and development of retinal blood vessels due to disturbances in the oxygen supply and metabolic demands during critical phases of fetal development.

The condition can be classified into various stages (1-5) based on its severity, with stages 4 and 5 being more severe forms that may lead to retinal detachment and blindness if left untreated. The pathogenesis of ROP involves an initial phase of vessel loss and regression in the central retina, followed by a secondary phase of abnormal neovascularization, which can cause fibrosis, traction, and ultimately, retinal detachment.

ROP is typically managed with a multidisciplinary approach involving ophthalmologists, neonatologists, and pediatricians. Treatment options include laser photocoagulation, cryotherapy, intravitreal anti-VEGF injections, or even surgical interventions to prevent retinal detachment and preserve vision. Regular screening examinations are crucial for early detection and timely management of ROP in at-risk infants.

Retinal diseases refer to a group of conditions that affect the retina, which is the light-sensitive tissue located at the back of the eye. The retina is responsible for converting light into electrical signals that are sent to the brain and interpreted as visual images. Retinal diseases can cause vision loss or even blindness, depending on their severity and location in the retina.

Some common retinal diseases include:

1. Age-related macular degeneration (AMD): A progressive disease that affects the central part of the retina called the macula, causing blurred or distorted vision.
2. Diabetic retinopathy: A complication of diabetes that can damage the blood vessels in the retina, leading to vision loss.
3. Retinal detachment: A serious condition where the retina becomes separated from its underlying tissue, requiring immediate medical attention.
4. Macular edema: Swelling or thickening of the macula due to fluid accumulation, which can cause blurred vision.
5. Retinitis pigmentosa: A group of inherited eye disorders that affect the retina's ability to respond to light, causing progressive vision loss.
6. Macular hole: A small break in the macula that can cause distorted or blurry vision.
7. Retinal vein occlusion: Blockage of the retinal veins that can lead to bleeding, swelling, and potential vision loss.

Treatment for retinal diseases varies depending on the specific condition and its severity. Some treatments include medication, laser therapy, surgery, or a combination of these options. Regular eye exams are essential for early detection and treatment of retinal diseases.

I am not aware of a specific medical definition for the term "China." Generally, it is used to refer to:

1. The People's Republic of China (PRC), which is a country in East Asia. It is the most populous country in the world and the fourth largest by geographical area. Its capital city is Beijing.
2. In a historical context, "China" was used to refer to various dynasties and empires that existed in East Asia over thousands of years. The term "Middle Kingdom" or "Zhongguo" (中国) has been used by the Chinese people to refer to their country for centuries.
3. In a more general sense, "China" can also be used to describe products or goods that originate from or are associated with the People's Republic of China.

If you have a specific context in which you encountered the term "China" related to medicine, please provide it so I can give a more accurate response.

The optic nerve, also known as the second cranial nerve, is the nerve that transmits visual information from the retina to the brain. It is composed of approximately one million nerve fibers that carry signals related to vision, such as light intensity and color, from the eye's photoreceptor cells (rods and cones) to the visual cortex in the brain. The optic nerve is responsible for carrying this visual information so that it can be processed and interpreted by the brain, allowing us to see and perceive our surroundings. Damage to the optic nerve can result in vision loss or impairment.

A laser is not a medical term per se, but a physical concept that has important applications in medicine. The term "LASER" stands for "Light Amplification by Stimulated Emission of Radiation." It refers to a device that produces and amplifies light with specific characteristics, such as monochromaticity (single wavelength), coherence (all waves moving in the same direction), and high intensity.

In medicine, lasers are used for various therapeutic and diagnostic purposes, including surgery, dermatology, ophthalmology, and dentistry. They can be used to cut, coagulate, or vaporize tissues with great precision, minimizing damage to surrounding structures. Additionally, lasers can be used to detect and measure physiological parameters, such as blood flow and oxygen saturation.

It's important to note that while lasers are powerful tools in medicine, they must be used by trained professionals to ensure safe and effective treatment.

"Fundus Oculi" is a medical term that refers to the back part of the interior of the eye, including the optic disc, macula, fovea, retinal vasculature, and peripheral retina. It is the area where light is focused and then transmitted to the brain via the optic nerve, forming visual images. Examinations of the fundus oculi are crucial for detecting various eye conditions such as diabetic retinopathy, macular degeneration, glaucoma, and other retinal diseases. The examination is typically performed using an ophthalmoscope or a specialized camera called a retinal camera.

An injection is a medical procedure in which a medication, vaccine, or other substance is introduced into the body using a needle and syringe. The substance can be delivered into various parts of the body, including into a vein (intravenous), muscle (intramuscular), under the skin (subcutaneous), or into the spinal canal (intrathecal or spinal).

Injections are commonly used to administer medications that cannot be taken orally, have poor oral bioavailability, need to reach the site of action quickly, or require direct delivery to a specific organ or tissue. They can also be used for diagnostic purposes, such as drawing blood samples (venipuncture) or injecting contrast agents for imaging studies.

Proper technique and sterile conditions are essential when administering injections to prevent infection, pain, and other complications. The choice of injection site depends on the type and volume of the substance being administered, as well as the patient's age, health status, and personal preferences.

"Chickens" is a common term used to refer to the domesticated bird, Gallus gallus domesticus, which is widely raised for its eggs and meat. However, in medical terms, "chickens" is not a standard term with a specific definition. If you have any specific medical concern or question related to chickens, such as food safety or allergies, please provide more details so I can give a more accurate answer.

An Eye Bank is an organization that collects, stores, and distributes donated human eyes for corneal transplantation and other ocular medical research purposes. The eye bank's primary function is to ensure the quality of the donated tissue and make it available for those in need of sight-restoring procedures.

The cornea, the clear front part of the eye, can be surgically transplanted from a deceased donor to a recipient with corneal damage or disease, thereby improving or restoring their vision. The eye bank's role includes obtaining consent for donation, retrieving the eyes from the donor, evaluating the tissue for suitability, preserving it properly, and then allocating it to surgeons for transplantation.

Eye banks follow strict medical guidelines and adhere to ethical standards to ensure the safety and quality of the donated tissues. The process involves screening potential donors for infectious diseases and other conditions that may affect the quality or safety of the cornea. Once deemed suitable, the corneas are carefully removed, preserved in specific solutions, and stored until they are needed for transplantation.

In addition to corneal transplants, eye banks also support research and education in ophthalmology by providing human eye tissues for various studies aimed at advancing our understanding of eye diseases and developing new treatments.

A cross-sectional study is a type of observational research design that examines the relationship between variables at one point in time. It provides a snapshot or a "cross-section" of the population at a particular moment, allowing researchers to estimate the prevalence of a disease or condition and identify potential risk factors or associations.

In a cross-sectional study, data is collected from a sample of participants at a single time point, and the variables of interest are measured simultaneously. This design can be used to investigate the association between exposure and outcome, but it cannot establish causality because it does not follow changes over time.

Cross-sectional studies can be conducted using various data collection methods, such as surveys, interviews, or medical examinations. They are often used in epidemiology to estimate the prevalence of a disease or condition in a population and to identify potential risk factors that may contribute to its development. However, because cross-sectional studies only provide a snapshot of the population at one point in time, they cannot account for changes over time or determine whether exposure preceded the outcome.

Therefore, while cross-sectional studies can be useful for generating hypotheses and identifying potential associations between variables, further research using other study designs, such as cohort or case-control studies, is necessary to establish causality and confirm any findings.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

Retinal vein occlusion (RVO) is a medical condition that occurs when one of the retinal veins, which drains blood from the retina, becomes blocked by a blood clot or atherosclerotic plaque. This blockage can cause hemorrhages, fluid accumulation, and damage to the retinal tissue, leading to vision loss.

There are two types of RVO: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). BRVO affects a smaller branch retinal vein, while CRVO affects the main retinal vein. CRVO is generally associated with more severe vision loss than BRVO.

Risk factors for RVO include hypertension, diabetes, high cholesterol levels, smoking, and glaucoma. Age is also a significant risk factor, as RVO becomes more common with increasing age. Treatment options for RVO may include controlling underlying medical conditions, laser therapy, intravitreal injections of anti-VEGF agents or steroids, and surgery in some cases.

Visual fields refer to the total area in which objects can be seen while keeping the eyes focused on a central point. It is the entire area that can be observed using peripheral (side) vision while the eye gazes at a fixed point. A visual field test is used to detect blind spots or gaps (scotomas) in a person's vision, which could indicate various medical conditions such as glaucoma, retinal damage, optic nerve disease, brain tumors, or strokes. The test measures both the central and peripheral vision and maps the entire area that can be seen when focusing on a single point.

'Diseases in Twins' is a field of study that focuses on the similarities and differences in the occurrence, development, and outcomes of diseases among twins. This research can provide valuable insights into the genetic and environmental factors that contribute to various medical conditions.

Twins can be classified into two types: monozygotic (identical) and dizygotic (fraternal). Monozygotic twins share 100% of their genes, while dizygotic twins share about 50%, similar to non-twin siblings. By comparing the concordance rates (the likelihood of both twins having the same disease) between monozygotic and dizygotic twins, researchers can estimate the heritability of a particular disease.

Studying diseases in twins also helps understand the role of environmental factors. When both twins develop the same disease, but they are discordant for certain risk factors (e.g., one twin smokes and the other does not), it suggests that the disease may have a stronger genetic component. On the other hand, when both twins share similar risk factors and develop the disease, it implies that environmental factors play a significant role.

Diseases in Twins research has contributed to our understanding of various medical conditions, including infectious diseases, cancer, mental health disorders, and developmental disorders. This knowledge can lead to better prevention strategies, early detection methods, and more targeted treatments for these diseases.

The retinal pigment epithelium (RPE) is a single layer of cells located between the photoreceptor cells of the retina and the choroid, which is a part of the eye containing blood vessels. The RPE plays a crucial role in maintaining the health and function of the photoreceptors by providing them with nutrients, removing waste products, and helping to regulate the light-sensitive visual pigments within the photoreceptors.

The RPE cells contain pigment granules that absorb excess light to prevent scattering within the eye and improve visual acuity. They also help to form the blood-retina barrier, which restricts the movement of certain molecules between the retina and the choroid, providing an important protective function for the retina.

Damage to the RPE can lead to a variety of eye conditions, including age-related macular degeneration (AMD), which is a leading cause of vision loss in older adults.

Follow-up studies are a type of longitudinal research that involve repeated observations or measurements of the same variables over a period of time, in order to understand their long-term effects or outcomes. In medical context, follow-up studies are often used to evaluate the safety and efficacy of medical treatments, interventions, or procedures.

In a typical follow-up study, a group of individuals (called a cohort) who have received a particular treatment or intervention are identified and then followed over time through periodic assessments or data collection. The data collected may include information on clinical outcomes, adverse events, changes in symptoms or functional status, and other relevant measures.

The results of follow-up studies can provide important insights into the long-term benefits and risks of medical interventions, as well as help to identify factors that may influence treatment effectiveness or patient outcomes. However, it is important to note that follow-up studies can be subject to various biases and limitations, such as loss to follow-up, recall bias, and changes in clinical practice over time, which must be carefully considered when interpreting the results.

Eye neoplasms, also known as ocular tumors or eye cancer, refer to abnormal growths of tissue in the eye. These growths can be benign (non-cancerous) or malignant (cancerous). Eye neoplasms can develop in various parts of the eye, including the eyelid, conjunctiva, cornea, iris, ciliary body, choroid, retina, and optic nerve.

Benign eye neoplasms are typically slow-growing and do not spread to other parts of the body. They may cause symptoms such as vision changes, eye pain, or a noticeable mass in the eye. Treatment options for benign eye neoplasms include monitoring, surgical removal, or radiation therapy.

Malignant eye neoplasms, on the other hand, can grow and spread rapidly to other parts of the body. They may cause symptoms such as vision changes, eye pain, floaters, or flashes of light. Treatment options for malignant eye neoplasms depend on the type and stage of cancer but may include surgery, radiation therapy, chemotherapy, or a combination of these treatments.

It is important to note that early detection and treatment of eye neoplasms can improve outcomes and prevent complications. Regular eye exams with an ophthalmologist are recommended for early detection and prevention of eye diseases, including eye neoplasms.

"Macaca mulatta" is the scientific name for the Rhesus macaque, a species of monkey that is native to South, Central, and Southeast Asia. They are often used in biomedical research due to their genetic similarity to humans.

The postoperative period is the time following a surgical procedure during which the patient's response to the surgery and anesthesia is monitored, and any complications or adverse effects are managed. This period can vary in length depending on the type of surgery and the individual patient's needs, but it typically includes the immediate recovery phase in the post-anesthesia care unit (PACU) or recovery room, as well as any additional time spent in the hospital for monitoring and management of pain, wound healing, and other aspects of postoperative care.

The goals of postoperative care are to ensure the patient's safety and comfort, promote optimal healing and rehabilitation, and minimize the risk of complications such as infection, bleeding, or other postoperative issues. The specific interventions and treatments provided during this period will depend on a variety of factors, including the type and extent of surgery performed, the patient's overall health and medical history, and any individualized care plans developed in consultation with the patient and their healthcare team.

A compound eye is a characteristic type of eye found in arthropods, including insects, crustaceans, and some extinct fossil groups. Each eye is composed of numerous individual photoreceptor units called ommatidia, which function together to provide a wide field of vision and excellent motion detection capabilities.

In an arthropod compound eye, each ommatidium contains a group of visual cells (called retinula cells) surrounding a central rhabdomere, which is the light-sensitive structure that converts light into electrical signals. The number of ommatidia in a compound eye can vary greatly between species and even within different regions of an individual's eye, ranging from just a few to tens of thousands.

Compound eyes offer several advantages for arthropods:

1. Wide Field of Vision: Compound eyes provide a panoramic view of the environment, allowing arthropods to detect predators, prey, or mates from various directions simultaneously.
2. Motion Detection: The apposition-type compound eye (one type of compound eye structure) is particularly adept at detecting motion due to the neural processing of signals between adjacent ommatidia. This allows arthropods to respond quickly to potential threats or opportunities.
3. Light Adaptation: Compound eyes can adapt to different light conditions, allowing arthropods to function effectively in both bright daylight and dimly lit environments. Some species have specialized regions within their compound eyes that are optimized for specific light conditions, such as the dorsal rim area in insects, which is sensitive to polarized skylight.
4. UV Sensitivity: Many arthropods can detect ultraviolet (UV) light due to the presence of photopigments within their ommatidia that absorb UV wavelengths. This ability allows them to perceive patterns and cues in their environment that are invisible to humans, such as floral guides in bees or mate-recognition signals in certain insects.

Despite their limitations in terms of resolution and image quality compared to vertebrate eyes, compound eyes have evolved to serve the unique needs and ecological roles of arthropods effectively.

Dizygotic twins, also known as fraternal twins, are a result of two separate sperm fertilizing two separate eggs during conception. These twins share about 50% of their genes, similar to any non-twin siblings. They may be of the same sex or different sexes and can vary in appearance, personality, and interests. Dizygotic twins typically do not share a placenta or a sac in the womb, but they may share a chorion (outer fetal membrane).

Eye protective devices are specialized equipment designed to protect the eyes from various hazards and injuries. They include items such as safety glasses, goggles, face shields, welding helmets, and full-face respirators. These devices are engineered to provide a barrier between the eyes and potential dangers like chemical splashes, impact particles, radiation, and other environmental hazards.

Safety glasses are designed to protect against flying debris, dust, and other airborne particles. They typically have side shields to prevent objects from entering the eye from the sides. Goggles offer a higher level of protection than safety glasses as they form a protective seal around the eyes, preventing liquids and fine particles from reaching the eyes.

Face shields and welding helmets are used in industrial settings to protect against radiation, sparks, and molten metal during welding or cutting operations. Full-face respirators are used in environments with harmful airborne particles or gases, providing protection for both the eyes and the respiratory system.

It is essential to choose the appropriate eye protective device based on the specific hazard present to ensure adequate protection.

Monozygotic twins, also known as identical twins, are derived from a single fertilized egg (ovum) that splits and develops into two separate embryos. This results in the formation of genetically identical individuals who share the same genetic material, with the exception of potential mutations that may occur after the split. Monozygotic twins have the same sex, blood type, and other genetic traits. They are a unique pair of siblings, sharing an extraordinary degree of resemblance in physical characteristics, abilities, and behaviors.

Prevalence, in medical terms, refers to the total number of people in a given population who have a particular disease or condition at a specific point in time, or over a specified period. It is typically expressed as a percentage or a ratio of the number of cases to the size of the population. Prevalence differs from incidence, which measures the number of new cases that develop during a certain period.

Organ size refers to the volume or physical measurement of an organ in the body of an individual. It can be described in terms of length, width, and height or by using specialized techniques such as imaging studies (like CT scans or MRIs) to determine the volume. The size of an organ can vary depending on factors such as age, sex, body size, and overall health status. Changes in organ size may indicate various medical conditions, including growths, inflammation, or atrophy.

A newborn infant is a baby who is within the first 28 days of life. This period is also referred to as the neonatal period. Newborns require specialized care and attention due to their immature bodily systems and increased vulnerability to various health issues. They are closely monitored for signs of well-being, growth, and development during this critical time.

Three-dimensional (3D) imaging in medicine refers to the use of technologies and techniques that generate a 3D representation of internal body structures, organs, or tissues. This is achieved by acquiring and processing data from various imaging modalities such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, or confocal microscopy. The resulting 3D images offer a more detailed visualization of the anatomy and pathology compared to traditional 2D imaging techniques, allowing for improved diagnostic accuracy, surgical planning, and minimally invasive interventions.

In 3D imaging, specialized software is used to reconstruct the acquired data into a volumetric model, which can be manipulated and viewed from different angles and perspectives. This enables healthcare professionals to better understand complex anatomical relationships, detect abnormalities, assess disease progression, and monitor treatment response. Common applications of 3D imaging include neuroimaging, orthopedic surgery planning, cancer staging, dental and maxillofacial reconstruction, and interventional radiology procedures.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

Penetrating eye injuries are a type of ocular trauma where a foreign object or substance pierces the outer layers of the eye and damages the internal structures. This can result in serious harm to various parts of the eye, such as the cornea, iris, lens, or retina, and may potentially cause vision loss or blindness if not promptly treated.

The severity of a penetrating eye injury depends on several factors, including the type and size of the object that caused the injury, the location of the wound, and the extent of damage to the internal structures. Common causes of penetrating eye injuries include sharp objects, such as metal shards or glass fragments, projectiles, such as pellets or bullets, and explosive materials.

Symptoms of a penetrating eye injury may include pain, redness, sensitivity to light, blurred vision, floaters, or the presence of a foreign body in the eye. If you suspect that you have sustained a penetrating eye injury, it is essential to seek immediate medical attention from an ophthalmologist or other healthcare professional with experience in treating eye trauma.

Treatment for penetrating eye injuries may include removing any foreign objects or substances from the eye, repairing damaged tissues, and administering medications to prevent infection and reduce inflammation. In some cases, surgery may be necessary to repair the injury and restore vision. Preventing eye injuries is crucial, and appropriate protective eyewear should be worn when engaging in activities that pose a risk of eye trauma.

Analysis of Variance (ANOVA) is a statistical technique used to compare the means of two or more groups and determine whether there are any significant differences between them. It is a way to analyze the variance in a dataset to determine whether the variability between groups is greater than the variability within groups, which can indicate that the groups are significantly different from one another.

ANOVA is based on the concept of partitioning the total variance in a dataset into two components: variance due to differences between group means (also known as "between-group variance") and variance due to differences within each group (also known as "within-group variance"). By comparing these two sources of variance, ANOVA can help researchers determine whether any observed differences between groups are statistically significant, or whether they could have occurred by chance.

ANOVA is a widely used technique in many areas of research, including biology, psychology, engineering, and business. It is often used to compare the means of two or more experimental groups, such as a treatment group and a control group, to determine whether the treatment had a significant effect. ANOVA can also be used to compare the means of different populations or subgroups within a population, to identify any differences that may exist between them.

Ocular fixation is a term used in ophthalmology and optometry to refer to the ability of the eyes to maintain steady gaze or visual focus on an object. It involves the coordinated movement of the extraocular muscles that control eye movements, allowing for clear and stable vision.

In medical terminology, fixation specifically refers to the state in which the eyes are aligned and focused on a single point in space. This is important for maintaining visual perception and preventing blurring or double vision. Ocular fixation can be affected by various factors such as muscle weakness, nerve damage, or visual processing disorders.

Assessment of ocular fixation is often used in eye examinations to evaluate visual acuity, eye alignment, and muscle function. Abnormalities in fixation may indicate the presence of underlying eye conditions or developmental delays that require further investigation and treatment.

Ophthalmic solutions are sterile, single-use or multi-dose preparations in a liquid form that are intended for topical administration to the eye. These solutions can contain various types of medications, such as antibiotics, anti-inflammatory agents, antihistamines, or lubricants, which are used to treat or prevent ocular diseases and conditions.

The pH and osmolarity of ophthalmic solutions are carefully controlled to match the physiological environment of the eye and minimize any potential discomfort or irritation. The solutions may be packaged in various forms, including drops, sprays, or irrigations, depending on the intended use and administration route.

It is important to follow the instructions for use provided by a healthcare professional when administering ophthalmic solutions, as improper use can lead to eye injury or reduced effectiveness of the medication.

"Sex factors" is a term used in medicine and epidemiology to refer to the differences in disease incidence, prevalence, or response to treatment that are observed between males and females. These differences can be attributed to biological differences such as genetics, hormones, and anatomy, as well as social and cultural factors related to gender.

For example, some conditions such as autoimmune diseases, depression, and osteoporosis are more common in women, while others such as cardiovascular disease and certain types of cancer are more prevalent in men. Additionally, sex differences have been observed in the effectiveness and side effects of various medications and treatments.

It is important to consider sex factors in medical research and clinical practice to ensure that patients receive appropriate and effective care.

Foreign bodies in the eye refer to any object or particle that is not normally present in the eye and becomes lodged in it. These foreign bodies can range from small particles like sand or dust to larger objects such as metal shavings or glass. They can cause irritation, pain, redness, watering, and even vision loss if they are not removed promptly and properly.

The symptoms of an eye foreign body may include:

* A feeling that something is in the eye
* Pain or discomfort in the eye
* Redness or inflammation of the eye
* Watering or tearing of the eye
* Sensitivity to light
* Blurred vision or difficulty seeing

If you suspect that you have a foreign body in your eye, it is important to seek medical attention immediately. An eye care professional can examine your eye and determine the best course of treatment to remove the foreign body and prevent any further damage to your eye.

Eye movement measurements, also known as oculometry, refer to the measurement and analysis of eye movements. This can include assessing the direction, speed, range, and patterns of eye movement. These measurements are often used in research and clinical settings to understand various aspects of vision, perception, and cognition. They can be used to diagnose and monitor conditions that affect eye movement, such as strabismus (crossed eyes), amblyopia (lazy eye), or neurological disorders. Additionally, eye movement measurements are also used in areas such as human-computer interaction, marketing research, and virtual reality to understand how individuals interact with their environment.

Medical Definition:

"Risk factors" are any attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease or injury. They can be divided into modifiable and non-modifiable risk factors. Modifiable risk factors are those that can be changed through lifestyle choices or medical treatment, while non-modifiable risk factors are inherent traits such as age, gender, or genetic predisposition. Examples of modifiable risk factors include smoking, alcohol consumption, physical inactivity, and unhealthy diet, while non-modifiable risk factors include age, sex, and family history. It is important to note that having a risk factor does not guarantee that a person will develop the disease, but rather indicates an increased susceptibility.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Ultrasonography, also known as sonography, is a diagnostic medical procedure that uses high-frequency sound waves (ultrasound) to produce dynamic images of organs, tissues, or blood flow inside the body. These images are captured in real-time and can be used to assess the size, shape, and structure of various internal structures, as well as detect any abnormalities such as tumors, cysts, or inflammation.

During an ultrasonography procedure, a small handheld device called a transducer is placed on the patient's skin, which emits and receives sound waves. The transducer sends high-frequency sound waves into the body, and these waves bounce back off internal structures and are recorded by the transducer. The recorded data is then processed and transformed into visual images that can be interpreted by a medical professional.

Ultrasonography is a non-invasive, painless, and safe procedure that does not use radiation like other imaging techniques such as CT scans or X-rays. It is commonly used to diagnose and monitor conditions in various parts of the body, including the abdomen, pelvis, heart, blood vessels, and musculoskeletal system.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Disease progression is the worsening or advancement of a medical condition over time. It refers to the natural course of a disease, including its development, the severity of symptoms and complications, and the impact on the patient's overall health and quality of life. Understanding disease progression is important for developing appropriate treatment plans, monitoring response to therapy, and predicting outcomes.

The rate of disease progression can vary widely depending on the type of medical condition, individual patient factors, and the effectiveness of treatment. Some diseases may progress rapidly over a short period of time, while others may progress more slowly over many years. In some cases, disease progression may be slowed or even halted with appropriate medical interventions, while in other cases, the progression may be inevitable and irreversible.

In clinical practice, healthcare providers closely monitor disease progression through regular assessments, imaging studies, and laboratory tests. This information is used to guide treatment decisions and adjust care plans as needed to optimize patient outcomes and improve quality of life.

Eye infections, also known as ocular infections, are conditions characterized by the invasion and multiplication of pathogenic microorganisms in any part of the eye or its surrounding structures. These infections can affect various parts of the eye, including the conjunctiva (conjunctivitis), cornea (keratitis), eyelid (blepharitis), or the internal structures of the eye (endophthalmitis, uveitis). The symptoms may include redness, pain, discharge, itching, blurred vision, and sensitivity to light. The cause can be bacterial, viral, fungal, or parasitic, and the treatment typically involves antibiotics, antivirals, or antifungals, depending on the underlying cause.

"Newborn animals" refers to the very young offspring of animals that have recently been born. In medical terminology, newborns are often referred to as "neonates," and they are classified as such from birth until about 28 days of age. During this time period, newborn animals are particularly vulnerable and require close monitoring and care to ensure their survival and healthy development.

The specific needs of newborn animals can vary widely depending on the species, but generally, they require warmth, nutrition, hydration, and protection from harm. In many cases, newborns are unable to regulate their own body temperature or feed themselves, so they rely heavily on their mothers for care and support.

In medical settings, newborn animals may be examined and treated by veterinarians to ensure that they are healthy and receiving the care they need. This can include providing medical interventions such as feeding tubes, antibiotics, or other treatments as needed to address any health issues that arise. Overall, the care and support of newborn animals is an important aspect of animal medicine and conservation efforts.

Treatment outcome is a term used to describe the result or effect of medical treatment on a patient's health status. It can be measured in various ways, such as through symptoms improvement, disease remission, reduced disability, improved quality of life, or survival rates. The treatment outcome helps healthcare providers evaluate the effectiveness of a particular treatment plan and make informed decisions about future care. It is also used in clinical research to compare the efficacy of different treatments and improve patient care.

"Age factors" refer to the effects, changes, or differences that age can have on various aspects of health, disease, and medical care. These factors can encompass a wide range of issues, including:

1. Physiological changes: As people age, their bodies undergo numerous physical changes that can affect how they respond to medications, illnesses, and medical procedures. For example, older adults may be more sensitive to certain drugs or have weaker immune systems, making them more susceptible to infections.
2. Chronic conditions: Age is a significant risk factor for many chronic diseases, such as heart disease, diabetes, cancer, and arthritis. As a result, age-related medical issues are common and can impact treatment decisions and outcomes.
3. Cognitive decline: Aging can also lead to cognitive changes, including memory loss and decreased decision-making abilities. These changes can affect a person's ability to understand and comply with medical instructions, leading to potential complications in their care.
4. Functional limitations: Older adults may experience physical limitations that impact their mobility, strength, and balance, increasing the risk of falls and other injuries. These limitations can also make it more challenging for them to perform daily activities, such as bathing, dressing, or cooking.
5. Social determinants: Age-related factors, such as social isolation, poverty, and lack of access to transportation, can impact a person's ability to obtain necessary medical care and affect their overall health outcomes.

Understanding age factors is critical for healthcare providers to deliver high-quality, patient-centered care that addresses the unique needs and challenges of older adults. By taking these factors into account, healthcare providers can develop personalized treatment plans that consider a person's age, physical condition, cognitive abilities, and social circumstances.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

A telomere is a region of repetitive DNA sequences found at the end of chromosomes, which protects the genetic data from damage and degradation during cell division. Telomeres naturally shorten as cells divide, and when they become too short, the cell can no longer divide and becomes senescent or dies. This natural process is associated with aging and various age-related diseases. The length of telomeres can also be influenced by various genetic and environmental factors, including stress, diet, and lifestyle.

A case-control study is an observational research design used to identify risk factors or causes of a disease or health outcome. In this type of study, individuals with the disease or condition (cases) are compared with similar individuals who do not have the disease or condition (controls). The exposure history or other characteristics of interest are then compared between the two groups to determine if there is an association between the exposure and the disease.

Case-control studies are often used when it is not feasible or ethical to conduct a randomized controlled trial, as they can provide valuable insights into potential causes of diseases or health outcomes in a relatively short period of time and at a lower cost than other study designs. However, because case-control studies rely on retrospective data collection, they are subject to biases such as recall bias and selection bias, which can affect the validity of the results. Therefore, it is important to carefully design and conduct case-control studies to minimize these potential sources of bias.

Aqueous humor is a clear, watery fluid that fills the anterior and posterior chambers of the eye. It is produced by the ciliary processes in the posterior chamber and circulates through the pupil into the anterior chamber, where it provides nutrients to the cornea and lens, maintains intraocular pressure, and helps to shape the eye. The aqueous humor then drains out of the eye through the trabecular meshwork and into the canal of Schlemm, eventually reaching the venous system.

An ethnic group is a category of people who identify with each other based on shared ancestry, language, culture, history, and/or physical characteristics. The concept of an ethnic group is often used in the social sciences to describe a population that shares a common identity and a sense of belonging to a larger community.

Ethnic groups can be distinguished from racial groups, which are categories of people who are defined by their physical characteristics, such as skin color, hair texture, and facial features. While race is a social construct based on physical differences, ethnicity is a cultural construct based on shared traditions, beliefs, and practices.

It's important to note that the concept of ethnic groups can be complex and fluid, as individuals may identify with multiple ethnic groups or switch their identification over time. Additionally, the boundaries between different ethnic groups can be blurred and contested, and the ways in which people define and categorize themselves and others can vary across cultures and historical periods.

Bacterial eye infections, also known as bacterial conjunctivitis or bacterial keratitis, are caused by the invasion of bacteria into the eye. The most common types of bacteria that cause these infections include Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae.

Bacterial conjunctivitis is an inflammation of the conjunctiva, the thin membrane that covers the white part of the eye and the inner surface of the eyelids. Symptoms include redness, swelling, pain, discharge, and a gritty feeling in the eye. Bacterial keratitis is an infection of the cornea, the clear front part of the eye. Symptoms include severe pain, sensitivity to light, tearing, and decreased vision.

Bacterial eye infections are typically treated with antibiotic eye drops or ointments. It is important to seek medical attention promptly if you suspect a bacterial eye infection, as untreated infections can lead to serious complications such as corneal ulcers and vision loss. Preventive measures include good hygiene practices, such as washing your hands frequently and avoiding touching or rubbing your eyes.

The ciliary body is a part of the eye's internal structure that is located between the choroid and the iris. It is composed of muscle tissue and is responsible for adjusting the shape of the lens through a process called accommodation, which allows the eye to focus on objects at varying distances. Additionally, the ciliary body produces aqueous humor, the clear fluid that fills the anterior chamber of the eye and helps to nourish the eye's internal structures. The ciliary body is also responsible for maintaining the shape and position of the lens within the eye.

In medical terms, "tears" are a clear, salty liquid that is produced by the tear glands (lacrimal glands) in our eyes. They serve to keep the eyes moist, protect against dust and other foreign particles, and help to provide clear vision by maintaining a smooth surface on the front of the eye. Tears consist of water, oil, and mucus, which help to prevent evaporation and ensure that the tears spread evenly across the surface of the eye. Emotional or reflexive responses, such as crying or yawning, can also stimulate the production of tears.

Binocular vision refers to the ability to use both eyes together to create a single, three-dimensional image of our surroundings. This is achieved through a process called binocular fusion, where the images from each eye are aligned and combined in the brain to form a unified perception.

The term "binocular vision" specifically refers to the way that our visual system integrates information from both eyes to create depth perception and enhance visual clarity. When we view an object with both eyes, they focus on the same point in space and send slightly different images to the brain due to their slightly different positions. The brain then combines these images to create a single, three-dimensional image that allows us to perceive depth and distance.

Binocular vision is important for many everyday activities, such as driving, reading, and playing sports. Disorders of binocular vision can lead to symptoms such as double vision, eye strain, and difficulty with depth perception.

In the context of medical terminology, I believe you may be referring to "pursuit" as it relates to neurological tests. A smooth pursuit is a type of eye movement in which the eyes smoothly and slowly follow a moving object. It requires coordination between the extraocular muscles, vestibular system, and visual system. If there are issues with any of these systems, smooth pursuit can be affected, leading to abnormalities such as jerky or saccadic movements.

Therefore, "smooth pursuit" is a medical term used to describe the normal, coordinated movement of the eyes that allows for the tracking of moving objects in a smooth and continuous manner.

Multivariate analysis is a statistical method used to examine the relationship between multiple independent variables and a dependent variable. It allows for the simultaneous examination of the effects of two or more independent variables on an outcome, while controlling for the effects of other variables in the model. This technique can be used to identify patterns, associations, and interactions among multiple variables, and is commonly used in medical research to understand complex health outcomes and disease processes. Examples of multivariate analysis methods include multiple regression, factor analysis, cluster analysis, and discriminant analysis.

Viral eye infections are caused by viruses that invade different parts of the eye, leading to inflammation and irritation. Some common types of viral eye infections include conjunctivitis (pink eye), keratitis, and dendritic ulcers. These infections can cause symptoms such as redness, watering, soreness, sensitivity to light, and discharge. In some cases, viral eye infections can also lead to complications like corneal scarring and vision loss if left untreated. They are often highly contagious and can spread through contact with contaminated surfaces or respiratory droplets. Antiviral medications may be used to treat certain types of viral eye infections, but in many cases, the infection will resolve on its own over time. Preventive measures such as good hygiene and avoiding touching the eyes can help reduce the risk of viral eye infections.

The term "European Continental Ancestry Group" is a medical/ethnic classification that refers to individuals who trace their genetic ancestry to the continent of Europe. This group includes people from various ethnic backgrounds and nationalities, such as Northern, Southern, Eastern, and Western European descent. It is often used in research and medical settings for population studies or to identify genetic patterns and predispositions to certain diseases that may be more common in specific ancestral groups. However, it's important to note that this classification can oversimplify the complex genetic diversity within and between populations, and should be used with caution.

Vision disorders refer to a wide range of conditions that affect the visual system and result in various symptoms, such as blurry vision, double vision, distorted vision, impaired depth perception, and difficulty with visual tracking or focusing. These disorders can be categorized into several types, including:

1. Refractive errors: These occur when the shape of the eye prevents light from focusing directly on the retina, resulting in blurry vision. Examples include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia (age-related loss of near vision).
2. Strabismus: Also known as crossed eyes or walleye, strabismus is a misalignment of the eyes where they point in different directions, which can lead to double vision or loss of depth perception.
3. Amblyopia: Often called lazy eye, amblyopia is a condition where one eye has reduced vision due to lack of proper visual development during childhood. It may be caused by strabismus, refractive errors, or other factors that interfere with normal visual development.
4. Accommodative disorders: These involve problems with the focusing ability of the eyes, such as convergence insufficiency (difficulty focusing on close objects) and accommodative dysfunction (inability to maintain clear vision at different distances).
5. Binocular vision disorders: These affect how the eyes work together as a team, leading to issues like poor depth perception, eye strain, and headaches. Examples include convergence insufficiency, divergence excess, and suppression.
6. Ocular motility disorders: These involve problems with eye movement, such as nystagmus (involuntary eye movements), strabismus, or restricted extraocular muscle function.
7. Visual processing disorders: These affect the brain's ability to interpret and make sense of visual information, even when the eyes themselves are healthy. Symptoms may include difficulty with reading, recognizing shapes and objects, and understanding spatial relationships.
8. Low vision: This term refers to significant visual impairment that cannot be fully corrected with glasses, contact lenses, medication, or surgery. It includes conditions like macular degeneration, diabetic retinopathy, glaucoma, and cataracts.
9. Blindness: Complete loss of sight in both eyes, which can be caused by various factors such as injury, disease, or genetic conditions.

Photic stimulation is a medical term that refers to the exposure of the eyes to light, specifically repetitive pulses of light, which is used as a method in various research and clinical settings. In neuroscience, it's often used in studies related to vision, circadian rhythms, and brain function.

In a clinical context, photic stimulation is sometimes used in the diagnosis of certain medical conditions such as seizure disorders (like epilepsy). By observing the response of the brain to this light stimulus, doctors can gain valuable insights into the functioning of the brain and the presence of any neurological disorders.

However, it's important to note that photic stimulation should be conducted under the supervision of a trained healthcare professional, as improper use can potentially trigger seizures in individuals who are susceptible to them.

Ophthalmology is a branch of medicine that deals with the diagnosis, treatment, and prevention of diseases and disorders of the eye and visual system. It is a surgical specialty, and ophthalmologists are medical doctors who complete additional years of training to become experts in eye care. They are qualified to perform eye exams, diagnose and treat eye diseases, prescribe glasses and contact lenses, and perform eye surgery. Some subspecialties within ophthalmology include cornea and external disease, glaucoma, neuro-ophthalmology, pediatric ophthalmology, retina and vitreous, and oculoplastics.

The oculomotor muscles are a group of extraocular muscles that control the movements of the eye. They include:

1. Superior rectus: This muscle is responsible for elevating the eye and helping with inward rotation (intorsion) when looking downwards.
2. Inferior rectus: It depresses the eye and helps with outward rotation (extorsion) when looking upwards.
3. Medial rectus: This muscle adducts, or moves, the eye towards the midline of the face.
4. Inferior oblique: The inferior oblique muscle intorts and elevates the eye.
5. Superior oblique: It extorts and depresses the eye.

These muscles work together to allow for smooth and precise movements of the eyes, enabling tasks such as tracking moving objects, reading, and maintaining visual fixation on a single point in space.

A cohort study is a type of observational study in which a group of individuals who share a common characteristic or exposure are followed up over time to determine the incidence of a specific outcome or outcomes. The cohort, or group, is defined based on the exposure status (e.g., exposed vs. unexposed) and then monitored prospectively to assess for the development of new health events or conditions.

Cohort studies can be either prospective or retrospective in design. In a prospective cohort study, participants are enrolled and followed forward in time from the beginning of the study. In contrast, in a retrospective cohort study, researchers identify a cohort that has already been assembled through medical records, insurance claims, or other sources and then look back in time to assess exposure status and health outcomes.

Cohort studies are useful for establishing causality between an exposure and an outcome because they allow researchers to observe the temporal relationship between the two. They can also provide information on the incidence of a disease or condition in different populations, which can be used to inform public health policy and interventions. However, cohort studies can be expensive and time-consuming to conduct, and they may be subject to bias if participants are not representative of the population or if there is loss to follow-up.

Ocular vision refers to the ability to process and interpret visual information that is received by the eyes. This includes the ability to see clearly and make sense of the shapes, colors, and movements of objects in the environment. The ocular system, which includes the eye and related structures such as the optic nerve and visual cortex of the brain, works together to enable vision.

There are several components of ocular vision, including:

* Visual acuity: the clarity or sharpness of vision
* Field of vision: the extent of the visual world that is visible at any given moment
* Color vision: the ability to distinguish different colors
* Depth perception: the ability to judge the distance of objects in three-dimensional space
* Contrast sensitivity: the ability to distinguish an object from its background based on differences in contrast

Disorders of ocular vision can include refractive errors such as nearsightedness or farsightedness, as well as more serious conditions such as cataracts, glaucoma, and macular degeneration. These conditions can affect one or more aspects of ocular vision and may require medical treatment to prevent further vision loss.

A questionnaire in the medical context is a standardized, systematic, and structured tool used to gather information from individuals regarding their symptoms, medical history, lifestyle, or other health-related factors. It typically consists of a series of written questions that can be either self-administered or administered by an interviewer. Questionnaires are widely used in various areas of healthcare, including clinical research, epidemiological studies, patient care, and health services evaluation to collect data that can inform diagnosis, treatment planning, and population health management. They provide a consistent and organized method for obtaining information from large groups or individual patients, helping to ensure accurate and comprehensive data collection while minimizing bias and variability in the information gathered.

The conjunctiva is the mucous membrane that lines the inner surface of the eyelids and covers the front part of the eye, also known as the sclera. It helps to keep the eye moist and protected from irritants. The conjunctiva can become inflamed or infected, leading to conditions such as conjunctivitis (pink eye).

Fluorescein angiography is a medical diagnostic procedure used in ophthalmology to examine the blood flow in the retina and choroid, which are the inner layers of the eye. This test involves injecting a fluorescent dye, Fluorescein, into a patient's arm vein. As the dye reaches the blood vessels in the eye, a specialized camera takes rapid sequences of photographs to capture the dye's circulation through the retina and choroid.

The images produced by fluorescein angiography can help doctors identify any damage to the blood vessels, leakage, or abnormal growth of new blood vessels. This information is crucial in diagnosing and managing various eye conditions such as age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, and inflammatory eye diseases.

It's important to note that while fluorescein angiography is a valuable diagnostic tool, it does carry some risks, including temporary side effects like nausea, vomiting, or allergic reactions to the dye. In rare cases, severe adverse reactions can occur, so patients should discuss these potential risks with their healthcare provider before undergoing the procedure.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Eyelids are the thin folds of skin that cover and protect the front surface (cornea) of the eye when closed. They are composed of several layers, including the skin, muscle, connective tissue, and a mucous membrane called the conjunctiva. The upper and lower eyelids meet at the outer corner of the eye (lateral canthus) and the inner corner of the eye (medial canthus).

The main function of the eyelids is to protect the eye from foreign particles, light, and trauma. They also help to distribute tears evenly over the surface of the eye through blinking, which helps to keep the eye moist and healthy. Additionally, the eyelids play a role in facial expressions and non-verbal communication.

Fungal eye infections, also known as fungal keratitis or ocular fungal infections, are caused by the invasion of fungi into the eye. The most common types of fungi that cause these infections include Fusarium, Aspergillus, and Candida. These infections can affect any part of the eye, including the cornea, conjunctiva, sclera, and vitreous humor.

Fungal eye infections often present with symptoms such as redness, pain, sensitivity to light, tearing, blurred vision, and discharge. In severe cases, they can lead to corneal ulcers, perforation of the eye, and even blindness if left untreated. Risk factors for fungal eye infections include trauma to the eye, contact lens wear, immunosuppression, and pre-existing eye conditions such as dry eye or previous eye surgery.

Diagnosis of fungal eye infections typically involves a thorough eye examination, including visual acuity testing, slit lamp examination, and sometimes corneal scrapings for microbiological culture and sensitivity testing. Treatment usually involves topical antifungal medications, such as natamycin or amphotericin B, and in some cases may require oral or intravenous antifungal therapy. In severe cases, surgical intervention may be necessary to remove infected tissue or repair any damage caused by the infection.

Photoreceptor cells in invertebrates are specialized sensory neurons that convert light stimuli into electrical signals. These cells are primarily responsible for the ability of many invertebrates to detect and respond to light, enabling behaviors such as phototaxis (movement towards or away from light) and vision.

Invertebrate photoreceptor cells typically contain light-sensitive pigments that absorb light at specific wavelengths. The most common type of photopigment is rhodopsin, which consists of a protein called opsin and a chromophore called retinal. When light hits the photopigment, it changes the conformation of the chromophore, triggering a cascade of molecular events that ultimately leads to the generation of an electrical signal.

Invertebrate photoreceptor cells can be found in various locations throughout the body, depending on their function. For example, simple eyespots containing a few photoreceptor cells may be scattered over the surface of the body in some species, while more complex eyes with hundreds or thousands of photoreceptors may be present in other groups. In addition to their role in vision, photoreceptor cells can also serve as sensory organs for regulating circadian rhythms, detecting changes in light intensity, and mediating social behaviors.

Parasitic eye infections are conditions characterized by the invasion and infestation of the eye or its surrounding structures by parasites. These can be protozoans, helminths, or ectoparasites. Examples of such infections include Acanthamoeba keratitis, which is caused by a free-living amoeba found in water and soil; Toxoplasmosis, which is caused by the protozoan Toxoplasma gondii; Loiasis, which is caused by the parasitic filarial worm Loa loa; and Demodicosis, which is caused by the mite Demodex folliculorum. Symptoms can vary depending on the type of parasite but often include redness, pain, discharge, and vision changes. Treatment typically involves antiparasitic medications and sometimes surgery to remove the parasites or damaged tissue. Prevention measures include good hygiene practices and avoiding contact with contaminated water or soil.

Eye pain is defined as discomfort or unpleasant sensations in the eye. It can be sharp, throbbing, stabbing, burning, or aching. The pain may occur in one or both eyes and can range from mild to severe. Eye pain can result from various causes, including infection, inflammation, injury, or irritation of the structures of the eye, such as the cornea, conjunctiva, sclera, or uvea. Other possible causes include migraines, optic neuritis, and glaucoma. It is essential to seek medical attention if experiencing sudden, severe, or persistent eye pain, as it can be a sign of a serious underlying condition that requires prompt treatment.

Strabismus is a condition of the ocular muscles where the eyes are not aligned properly and point in different directions. One eye may turn inward, outward, upward, or downward while the other one remains fixed and aligns normally. This misalignment can occur occasionally or constantly. Strabismus is also commonly referred to as crossed eyes or walleye. The condition can lead to visual impairments such as amblyopia (lazy eye) and depth perception problems if not treated promptly and effectively, usually through surgery, glasses, or vision therapy.

Eye evisceration is a surgical procedure in which the contents of the eye are removed, leaving the sclera (the white part of the eye) and the eyelids intact. This procedure is typically performed to treat severe eye injuries or infections, as well as to alleviate pain in blind eyes. After the eye contents are removed, an orbital implant is placed in the eye socket to restore its shape and volume. The eyelids are then closed over the implant, creating a smooth appearance. It's important to note that although the eye appears to have some cosmetic normality after the procedure, vision cannot be restored.

Genetic predisposition to disease refers to an increased susceptibility or vulnerability to develop a particular illness or condition due to inheriting specific genetic variations or mutations from one's parents. These genetic factors can make it more likely for an individual to develop a certain disease, but it does not guarantee that the person will definitely get the disease. Environmental factors, lifestyle choices, and interactions between genes also play crucial roles in determining if a genetically predisposed person will actually develop the disease. It is essential to understand that having a genetic predisposition only implies a higher risk, not an inevitable outcome.

An eye hemorrhage, also known as subconjunctival hemorrhage, is a condition where there is bleeding in the eye, specifically under the conjunctiva which is the clear membrane that covers the white part of the eye (sclera). This membrane has tiny blood vessels that can rupture and cause blood to accumulate, leading to a visible red patch on the surface of the eye.

Eye hemorrhages are usually painless and harmless, and they often resolve on their own within 1-2 weeks without any treatment. However, if they occur frequently or are accompanied by other symptoms such as vision changes, pain, or sensitivity to light, it is important to seek medical attention as they could indicate a more serious underlying condition. Common causes of eye hemorrhages include trauma, high blood pressure, blood thinners, and aging.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

Amplified Fragment Length Polymorphism (AFLP) analysis is a molecular biology technique used for DNA fingerprinting, genetic mapping, and population genetics studies. It is based on the selective amplification of restriction fragments from a total digest of genomic DNA, followed by separation and detection of the resulting fragments using polyacrylamide gel electrophoresis.

In AFLP analysis, genomic DNA is first digested with two different restriction enzymes, one that cuts frequently (e.g., EcoRI) and another that cuts less frequently (e.g., MseI). The resulting fragments are then ligated to adapter sequences that provide recognition sites for PCR amplification.

Selective amplification of the restriction fragments is achieved by using primers that anneal to the adapter sequences and contain additional selective nucleotides at their 3' ends. This allows for the amplification of a subset of the total number of restriction fragments, resulting in a pattern of bands that is specific to the DNA sample being analyzed.

The amplified fragments are then separated by size using polyacrylamide gel electrophoresis and visualized by staining with a fluorescent dye. The resulting banding pattern can be used for various applications, including identification of genetic differences between individuals, detection of genomic alterations in cancer cells, and analysis of population structure and diversity.

Overall, AFLP analysis is a powerful tool for the study of complex genomes and has been widely used in various fields of biology, including plant and animal breeding, forensic science, and medical research.

Macular degeneration, also known as age-related macular degeneration (AMD), is a medical condition that affects the central part of the retina, called the macula. The macula is responsible for sharp, detailed vision, which is necessary for activities such as reading, driving, and recognizing faces.

In AMD, there is a breakdown or deterioration of the macula, leading to gradual loss of central vision. There are two main types of AMD: dry (atrophic) and wet (exudative). Dry AMD is more common and progresses more slowly, while wet AMD is less common but can cause rapid and severe vision loss if left untreated.

The exact causes of AMD are not fully understood, but risk factors include age, smoking, family history, high blood pressure, obesity, and exposure to sunlight. While there is no cure for AMD, treatments such as vitamin supplements, laser therapy, and medication injections can help slow its progression and reduce the risk of vision loss.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Blindness is a condition of complete or near-complete vision loss. It can be caused by various factors such as eye diseases, injuries, or birth defects. Total blindness means that a person cannot see anything at all, while near-complete blindness refers to having only light perception or the ability to perceive the direction of light, but not able to discern shapes or forms. Legal blindness is a term used to define a certain level of visual impairment that qualifies an individual for government assistance and benefits; it usually means best corrected visual acuity of 20/200 or worse in the better eye, or a visual field no greater than 20 degrees in diameter.

Amblyopia is a medical condition that affects the visual system, specifically the way the brain and eyes work together. It is often referred to as "lazy eye" and is characterized by reduced vision in one or both eyes that is not correctable with glasses or contact lenses alone. This occurs because the brain favors one eye over the other, causing the weaker eye to become neglected and underdeveloped.

Amblyopia can result from various conditions such as strabismus (eye misalignment), anisometropia (significant difference in prescription between the two eyes), or deprivation (such as a cataract that blocks light from entering the eye). Treatment for amblyopia typically involves correcting any underlying refractive errors, patching or blurring the stronger eye to force the weaker eye to work, and/or vision therapy. Early intervention is crucial to achieve optimal visual outcomes.

Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.

The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.

In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.

Electroretinography (ERG) is a medical test used to evaluate the functioning of the retina, which is the light-sensitive tissue located at the back of the eye. The test measures the electrical responses of the retina to light stimulation.

During the procedure, a special contact lens or electrode is placed on the surface of the eye to record the electrical activity generated by the retina's light-sensitive cells (rods and cones) and other cells in the retina. The test typically involves presenting different levels of flashes of light to the eye while the electrical responses are recorded.

The resulting ERG waveform provides information about the overall health and function of the retina, including the condition of the photoreceptors, the integrity of the inner retinal layers, and the health of the retinal ganglion cells. This test is often used to diagnose and monitor various retinal disorders, such as retinitis pigmentosa, macular degeneration, and diabetic retinopathy.

Telomere shortening is the gradual loss of repetitive DNA sequences and associated proteins from the ends of chromosomes that occurs naturally as cells divide. Telomeres are protective caps at the ends of chromosomes, which prevent the loss of genetic information during cell division. However, each time a cell divides, its telomeres become slightly shorter. When telomeres reach a critically short length, the cell can no longer divide and becomes senescent or dies. This process is thought to contribute to aging and age-related diseases, as well as to the development of cancer.

Telomere homeostasis refers to the balance between the processes that maintain or lengthen telomeres and those that shorten them. Telomeres are the protective caps at the ends of chromosomes, which progressively shorten each time a cell divides due to the inability of conventional DNA polymerase to fully replicate the ends of linear chromosomes.

The maintenance of telomere length is critical for maintaining genomic stability and preventing cellular senescence or apoptosis (programmed cell death). Telomere homeostasis involves several mechanisms, including the enzyme telomerase, which adds DNA repeats to the ends of telomeres, and other protective proteins that bind to telomeres and prevent their degradation.

On the other hand, processes such as oxidative stress, inflammation, and genotoxic agents can cause excessive telomere shortening, leading to cellular dysfunction and aging-related diseases. Therefore, maintaining telomere homeostasis is essential for healthy aging and preventing age-related diseases.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Biomechanics is the application of mechanical laws to living structures and systems, particularly in the field of medicine and healthcare. A biomechanical phenomenon refers to a observable event or occurrence that involves the interaction of biological tissues or systems with mechanical forces. These phenomena can be studied at various levels, from the molecular and cellular level to the tissue, organ, and whole-body level.

Examples of biomechanical phenomena include:

1. The way that bones and muscles work together to produce movement (known as joint kinematics).
2. The mechanical behavior of biological tissues such as bone, cartilage, tendons, and ligaments under various loads and stresses.
3. The response of cells and tissues to mechanical stimuli, such as the way that bone tissue adapts to changes in loading conditions (known as Wolff's law).
4. The biomechanics of injury and disease processes, such as the mechanisms of joint injury or the development of osteoarthritis.
5. The use of mechanical devices and interventions to treat medical conditions, such as orthopedic implants or assistive devices for mobility impairments.

Understanding biomechanical phenomena is essential for developing effective treatments and prevention strategies for a wide range of medical conditions, from musculoskeletal injuries to neurological disorders.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Ocular convergence is the normal, inward movement of both eyes towards each other to focus on a nearby object. This coordinated action allows for single, clear vision (binocular vision) of the object. It is an important component of visual function and is controlled by the brain receiving input from the muscles that move the eyes.

Convergence insufficiency is a common condition where the eyes have difficulty maintaining alignment during close work, such as reading or using a computer. This can result in eye strain, double vision, and difficulty concentrating. Treatment for convergence insufficiency may include vision therapy, exercises to improve convergence ability, and/or the use of prism lenses.

Ophthalmologic surgical procedures refer to various types of surgeries performed on the eye and its surrounding structures by trained medical professionals called ophthalmologists. These procedures aim to correct or improve vision, diagnose and treat eye diseases or injuries, and enhance the overall health and functionality of the eye. Some common examples of ophthalmologic surgical procedures include:

1. Cataract Surgery: This procedure involves removing a cloudy lens (cataract) from the eye and replacing it with an artificial intraocular lens (IOL).
2. LASIK (Laser-Assisted In Situ Keratomileusis): A type of refractive surgery that uses a laser to reshape the cornea, correcting nearsightedness, farsightedness, and astigmatism.
3. Glaucoma Surgery: Several surgical options are available for treating glaucoma, including laser trabeculoplasty, traditional trabeculectomy, and various drainage device implantations. These procedures aim to reduce intraocular pressure (IOP) and prevent further optic nerve damage.
4. Corneal Transplant: This procedure involves replacing a damaged or diseased cornea with a healthy donor cornea to restore vision and improve the eye's appearance.
5. Vitreoretinal Surgery: These procedures focus on treating issues within the vitreous humor (gel-like substance filling the eye) and the retina, such as retinal detachment, macular holes, or diabetic retinopathy.
6. Strabismus Surgery: This procedure aims to correct misalignment of the eyes (strabismus) by adjusting the muscles responsible for eye movement.
7. Oculoplastic Surgery: These procedures involve reconstructive, cosmetic, and functional surgeries around the eye, such as eyelid repair, removal of tumors, or orbital fracture repairs.
8. Pediatric Ophthalmologic Procedures: Various surgical interventions are performed on children to treat conditions like congenital cataracts, amblyopia (lazy eye), or blocked tear ducts.

These are just a few examples of ophthalmic surgical procedures. The specific treatment plan will depend on the individual's condition and overall health.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Head movements refer to the voluntary or involuntary motion of the head in various directions. These movements can occur in different planes, including flexion (moving the head forward), extension (moving the head backward), rotation (turning the head to the side), and lateral bending (leaning the head to one side).

Head movements can be a result of normal physiological processes, such as when nodding in agreement or shaking the head to indicate disagreement. They can also be caused by neurological conditions, such as abnormal head movements in patients with Parkinson's disease or cerebellar disorders. Additionally, head movements may occur in response to sensory stimuli, such as turning the head toward a sound.

In a medical context, an examination of head movements can provide important clues about a person's neurological function and help diagnose various conditions affecting the brain and nervous system.

Optic nerve diseases refer to a group of conditions that affect the optic nerve, which transmits visual information from the eye to the brain. These diseases can cause various symptoms such as vision loss, decreased visual acuity, changes in color vision, and visual field defects. Examples of optic nerve diseases include optic neuritis (inflammation of the optic nerve), glaucoma (damage to the optic nerve due to high eye pressure), optic nerve damage from trauma or injury, ischemic optic neuropathy (lack of blood flow to the optic nerve), and optic nerve tumors. Treatment for optic nerve diseases varies depending on the specific condition and may include medications, surgery, or lifestyle changes.

A sarcomere is the basic contractile unit in a muscle fiber, and it's responsible for generating the force necessary for muscle contraction. It is composed of several proteins, including actin and myosin, which slide past each other to shorten the sarcomere during contraction. The sarcomere extends from one Z-line to the next in a muscle fiber, and it is delimited by the Z-discs where actin filaments are anchored. Sarcomeres play a crucial role in the functioning of skeletal, cardiac, and smooth muscles.

Visual perception refers to the ability to interpret and organize information that comes from our eyes to recognize and understand what we are seeing. It involves several cognitive processes such as pattern recognition, size estimation, movement detection, and depth perception. Visual perception allows us to identify objects, navigate through space, and interact with our environment. Deficits in visual perception can lead to learning difficulties and disabilities.

A vestibulo-ocular reflex (VOR) is a automatic motion of the eyes that helps to stabilize images on the retina during head movement. It is mediated by the vestibular system, which includes the semicircular canals and otolith organs in the inner ear.

When the head moves, the movement is detected by the vestibular system, which sends signals to the oculomotor nuclei in the brainstem. These nuclei then generate an eye movement that is equal and opposite to the head movement, allowing the eyes to remain fixed on a target while the head is moving. This reflex helps to maintain visual stability during head movements and is essential for activities such as reading, walking, and driving.

The VOR can be tested clinically by having the patient follow a target with their eyes while their head is moved passively. If the VOR is functioning properly, the eyes should remain fixed on the target despite the head movement. Abnormalities in the VOR can indicate problems with the vestibular system or the brainstem.

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The visual surface of the eye is rather small (about 20% of the length of the cephalon), with the front about halflength of the ... with the front straight and confluent with the eye ridges. The occipital ring is about as wide as the border and the axial ... consisting almost fully of the axis and post axial boss, with two vaguely defined axial rings. During the ontogenetic ... anterior of the visual surface is parallel to the midline or converges slightly forward and from the back of the eye diverges ...
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... reduction in eye axial length, and narrow iridocorneal angles. Eyes from individuals with angle-closure glaucoma (ACG) often ... The clinical features of this condition include extreme hyperopia due to short axial length with essentially normal anterior ... The gene is located on long arm of chromosome 2 (2q37.1). The encoded protein is 603 amino acid residues in length with a ... The fundus of the eye shows crowded optical discs, tortuous vessels and an abnormal foveal avascular zone. Mice homozygous for ...
pygidium) has six axial rings that decrease in size backwards and four or five pairs of rearward pointing marginal spines. ... Narrow occular ridges curve backwards from the front of the glabella to the small, outwardly-bowed eyes. The librigenae narrow ... Cephalon, thorax and pygidium are of approximately equal length. Olenoides serratus is one of about twenty species of which the ...
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Axial myopia is attributed to an increase in the eye's axial length Refractive myopia is attributed to the condition of the ... Scleral buckles, used in the repair of retinal detachments may induce myopia by increasing the axial length of the eye. Index ... Upon routine examination of the eyes, the vast majority of myopic eyes appear structurally identical to nonmyopic eyes.[ ... "Axial Eye Length after Retinal Detachment Surgery". Collegium Antropologicum. 29 - Supplement 1 (1): 25-27. PMID 16193671. ...
The optics of the eye including its refractive power and axial length also play a major role in retinal image size.[citation ... The person then closes one eye, and then the other. The person should notice that the target appears larger to the eye that it ... Eyes in the Storm-President Hopkins' Dilemma: The Dartmouth Eye Institute, Norwich, Vermont: Norwich Book Press, p. 288 ... having significantly different refractive errors between each eye) or antimetropia (being myopic (nearsighted) in one eye and ...
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That is, the operated eye will be more short sighted after the operation due to the buckle causing the axial length to increase ... The retina is a thin layer of light-sensitive tissue on the back wall of the eye. The optical system of the eye focuses light ... Retinal detachment does not occur as a result of eye strain, bending, or heavy lifting.[attribution needed] Retinoschisis - Eye ... Ghazi, NG; Green, WR (2002). "Pathology and pathogenesis of retinal detachment". Eye. 16 (4): 411-421. doi:10.1038/sj.eye. ...
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... as choroidal thickness decreases with age and increasing axial length of the eye causing near-sightedness (myopia). Within the ... Pachychoroid disorders of the macula represent a group of diseases affecting the central part of the retina of the eye, the ... Anti-VEGF therapy, which is injected directly into the eye (intravitreally), has proven to be an effective therapy in this case ... eyes are classified as having an uncomplicated pachychoroid. It is assumed that a large part of the population has a thickened ...
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Exceedingly small changes in axial length of the eyeball (18.6-19.2 μm) are caused by the action of the ciliary muscle during ... Grierson, Ian (2000). "Exercises for Eyes as an Alternative to Glasses". The Eye Book: Eyes and Eye Problems Explained. ... crossed-eye, lazy eye, and to more serious eye conditions such as cataracts and glaucoma. His therapies were based on these ... "eye exercises, muscle relaxation techniques, biofeedback, eye patches, or eye massages", "alone or in combinations". No ...
Later procedures focused on modifying the axial length of the eye, by preventing elongation and staphyloma progression by ... Eye. Ward, B., Tarutta, E., & Mayer, M. (2009). The efficacy and safety of posterior pole buckles in the control of progressive ... in early literature aimed at shortening the length of the eyeball by resecting a ring of sclera from the equator of the eye. ... Eye, 23(12), 2169-2174. Thompson, F., Scleral Reinforcement. Chapter 10., in Myopia Surgery. 1990, Macmillan: New York. p. 267- ...
According to these fossils, conodonts had large eyes, fins with fin rays, chevron-shaped muscles and axial line, which were ... While Clydagnathus and Panderodus had lengths only reaching 4-5 cm (1.6-2.0 in), Promissum is estimated to reach 40 cm (16 in) ... The feeding apparatus of ozarkodinids is composed of an axial Sa element at the front, flanked by two groups of four close-set ... There are other examples of conodont animals that only preserve the head region, including eyes, of the animals known from the ...
This short length is achieved by the spiral valve with multiple turns within a single short section instead of a very long tube ... These markings run from their eyes to their first dorsal fin and then across the rest of their bodies. Both dorsal fins are ... Port Jackson Shark movements have been quantified using tri-axial accelerometers. These sensors function like Fitbits, but for ... Identification of this species is very easy due to the pattern of harness-like markings that cross the eyes, run along the back ...
Many non-proprietary co-axial power plugs are 5.5 mm (0.22 in) in outside diameter (OD) and 9.5 mm (0.37 in) in length. Two pin ... If the size is not known, it is difficult to distinguish by eye or measurement between the 2.1mm and 2.5mm ID plugs; some ...
Axial sculpture is absent or feebly developed. The aperture is ovate. The columellar margin is smoot. The outer lip has a ... The eyes are located externally near the base of cylindrical tentacles. The radula formula is 1-0-R-0-1 The duplex radular ... This family consists of moderately sized shells, usually between 20 and 30 mm, but in Nihonia maxima the length of shell can ...
... whenever the disparity between the two eyes is due to a difference in axial length of the eyes. When a refractive error is ... Knapp's Rule states that lenses placed at the anterior focal point of the eye, generally 15 mm in front of the eye, will create ... One difficulty, then, in prescribing glasses to an individual with a disparity in refractive error between the two eyes is that ... a disparity in image size between the two eyes may be created. There is some controversy as to the soundness of Knapp's Rule. ...
That condition of the normal eye is achieved when the refractive power of the cornea and eye lens and the axial length of the ... "Photorefractive Keratectomy (PRK) Eye Surgery" Mutti, DO (2005). "Axial Growth and Changes in Lenticular and Corneal Power ... eye at a distance of 20 ft (the second number). Eyes that have enough myopia (near-sighted), hyperopia (far-sighted, excluding ... the eye presents defects sufficiently pronounced to be easily established." Physiologic Optics: Dioptrics of the Eye, Functions ...
With one eye of average size, the asymmetry often becomes much more severe as the child ages. An axial length of less than 16 ... An ultrasound may also be conducted to confirm whether the axial length of the eye is clinically below average (i.e. at least 2 ... as a small eye is usually far-sighted. When one of the eyes is unaffected, caution should be taken to guard this 'good' eye and ... While the axis of an adult human eye has an average length of about 23.8 mm (0.94 in), a diagnosis of microphthalmia generally ...
The glabella is wide at its base, normally parallel sided but may taper gently or be at its widest at half length. Glabellar ... The pygidial axis is long and strongly tapered with 10 or more axial rings. The segmentation of the axis, however, is often ... All Weymouthiidae lack eyes. The thorax consists of three rings when known (Mallagnostus, Marocconus, Serrodiscus, Tannudiscus ... and forms with a primitive occipital structure but with a greatly increased numbers of axial segments. KOBAYASHI T. 1943. Brief ...
Because its eyes were comparable in size to those of modern day-living (diurnal) lemurs, Pachylemur was probably diurnal as ... Unlike ruffed lemurs, the fore- and hindlimbs of Pachylemur were nearly the same length, and therefore it was likely to be a ... Yet more recent analysis of its axial and appendicular skeleton-particularly the vertebrae and femur-suggests that it was a ... The skull of Pachylemur is relatively broad, but the orbits (eye sockets) are smaller and oriented more towards the front than ...
Differences in Axial Length and Anterior Chamber Depth among Keratoconic, Myopic and Emmetropic Eyes Doi: 10.36351/pjo. ... Purpose: To report variation of the axial length (AL) and anterior chamber depth (ACD) among keratoconic (KC) eyes compared to ... Methods: One-hundred and twenty-four eyes of 62 patients were divided into KC group (n =17, eyes=34), myopic group (n=28, eyes= ... Differences in Axial Length and Anterior Chamber Depth among Keratoconic, Myopic and Emmetropic Eyes: Doi: 10.36351/pjo. ...
Changing the axial length of the eyeball. -Changing the shape of the cornea. Focusing the light scattered by objects in a three ... The most complex Molluscan eye is the Cephalopod eye which is superficially similar structure and function to a vertebrate eye ... The young human eye can change focus from distance (infinity) to as near as 6.5 cm from the eye. This dramatic change in focal ... To focus its eyes, a lamprey flattens the cornea using muscles outside of the eye and pushes the lens backwards. While not ...
2] and short axial eye length. Studies have suggested that increased iris thickness and cross-sectional area are also ... Further, the term primary angle closure suspect refers to an eye in which there is contact between the peripheral iris and the ... Aqueous humor is produced by the ciliary body in the posterior chamber of the eye. It diffuses from the posterior chamber, ... As the lens swells, it crowds the anterior chamber and, through mechanisms previously discussed at length, leads to an increase ...
... axial length measurement (IOLMaster; Carl Zeiss Meditec, Dublin, Ca, USA, Aviso; Quantel medical, Quebec, Canada), stereo-disc ... In this study, PAC eyes with a history of ACG attack were compared with fellow PAC eyes without attack and found no significant ... The study evaluated 54 eyes of 27 patients with PAC, and two eyes of one patient, which developed bullous keratopathy due to ... Biometrics of PAC eyes have been subjected to study for many years. Recent interest in CCT is due to its influence on the ...
To evaluate the time trend of axial length (AL) and associated factors in 4- and 5-year-old children in Shanghai from 2013 to ... Both eyes of each child were examined, but only data from the right eye was used for the analysis. Spherical equivalent (SE) ... Table 3 Multivariate linear regression analysis for potential factors associated with axial length in 4-year-old children. Full ... Table 4 Multivariate linear regression analysis for potential factors associated with axial length in 5-year-old children. Full ...
Myopia develops from a mismatch of the eyes anatomical axial length and its focal length, as determined by the combined ... Myopia in humans results from an imbalance between the refractive power of the cornea and lens and the axial length of the eye ... Axial Length: A Risk Factor for Cataractogenesis. Ziqiang Wu, Jennifer I Lim, Srinivas R Sadda ... The eye as a window to the brain. Misha L Pless. Over the last 20 years, it has become evident that the age-old expression, " ...
Innovative therapy substantially slows myopia progression and eye elongation as measured by refractive error and axial length ... as measured by mean axial elongation of the eye when compared to the children in the control group wearing a single vision 1- ... "Early intervention by parents, in partnership with eye care professionals, is essential the near- and long-term health and well ...
In particular, the SLITRK6 protein influences the length of the eyeball (axial length), which affects whether a person will be ... The protein produced from this gene is found primarily in the inner ear and the eye. This protein promotes growth and survival ... It also controls (regulates) the growth of the eye after birth. ...
... in eyes with axial length greater than 26 mm, the anatomic axial length is a mean 0.8 mm longer than the optical axial length.5 ... the device calculates the length of the eye.. It is hard to conceive of how the precision of axial length measurement can be ... ultrasound measures the anatomic axial length of the eye, from the anterior pole to the posterior pole, not the optical axial ... and other parameters in addition to axial length. By the 1990s, ultrasound measurement of axial length was accurate to ...
In total, 97% of operated eyes achieved an UDVA of 20/25 or better. ≥1 line was gained for 9 eyes (26%), with 25 eyes (71%) ... In total, 97% of operated eyes achieved an UDVA of 20/25 or better. ≥ 1 line was gained for 9 eyes (26%), with 25 eyes (71%) ... Twenty-four (69%) and 33 (94%) eyes, respectively, were within ±0.50 D and ±1.0 D of target refraction. From 3 months to 4 ... 24 (69%) and 33 (94%) eyes, respectively, were within ± 0.50 D and ± 1.0 D of target refraction. From three months to four ...
... reduce axial length.. At two years, in 21 studies (4169 participants), the median change in axial length for controls was 0.56 ... This puts the eye at greater risk of eye diseases such as glaucoma, maculopathy and retinal detachment later in life. ... the median change in axial length for controls was 0.31 mm. The following interventions may reduce axial elongation compared to ... We rated the certainty of evidence using the GRADE approach for the outcomes: change in SER and axial length at one and two ...
Keratometry also was performed on each eye. Anterior chamber depth, lens thickness, vitreous chamber depth, and axial length ... and greater axial lengths. CONCLUSIONS: A tendency for the cornea to flatten less rapidly in the periphery with increasing ... and between Q and axial length (r = 0.24, P , 0.05). The association between Q and corneal radius of curvature was found not to ... Eyes with higher levels of myopia had steeper central corneal curvatures, deeper anterior and vitreous chambers, ...
Radial cable exit versions with swivel rod eye ends or axial termination versions with either M-12 connector or cable can be ... The ILPS series also includes the ILPS-19 series for applications where a shorter length and smaller diameter body is required ... With their compact design, superior performance, and excellent stroke-to-length ratio, ILPS-27 sensors are ideal for both ...
... including an acquisition step of acquiring OCT data of an eye to be examined based on a spectral interference signal output ... The first fundus position is a fundus position assumed in an eye with short eye axial length or an eye with long eye axial ... eye axial length or an eye with long eye axial length to a second fundus position which is a fundus position assumed in an eye ... position assumed in the eye with short eye axial length and the fundus position assumed in the eye with long eye axial length. ...
This multicentre cohort study will include 618 patients scheduled for lens surgery with an axial length of at least 25.0 mm. ... To analyse these eyes in comparison to other eyes screened to find factors responsible for 20/40 and J4 unaided vision. ... Microorganisms identified in the eyes with MK will be compared to the control fellow eye and other control groups and ... The vRESPOND study will develop the methodology to build personalized eye-models which can be used to study the exact path of ...
Posterior Eye Segment 100% * Eye Shape 100% * Axial Length 80% * Equatorial Diameter 80% ... Dive into the research topics of Effects of hemiretinal form deprivation on central refractive development and posterior eye ... Effects of hemiretinal form deprivation on central refractive development and posterior eye shape in chicks. ...
The system can provide corneal information, fundus information and axial length information, so that the user can operate a ... Multifunctional Eye Health Monitoring Device (ARD/300). Project Title:. Multifunctional Eye Health Monitoring Device (ARD/300) ... Eyes are the most delicate and sophisticated sense organs of the human body. People use their eyes to perceive the color and ... In this regard, eye health has increasingly received great attention, and various eye monitoring devices have also accordingly ...
... it should be the aim of eye care professionals to do the same for axial length measurement in pediatric myopia management. ... The main cause of myopia is an increase in axial length. The ocular morbidity increases per millimeter of axial length, and ... Here are details of leading optical biometers for measuring axial length:. Topcon Aladdin-M. Aladdin-M offers an affordable, ... Axial length (AL) measurement has not traditionally been considered part of mainstream optometry. The same could have been said ...
VEGF levels decreased with an increase in the axial length (p,0.001). PEDF levels tended to be higher in the high myopia group ... in high myopic eyes and control eyes. Methods: Aqueous humor samples were collected from 21 highly myopic eyes of 20 patients ( ... Of the 21 high myopic eyes, 13 had no complications secondary to high myopia (high myopia with no complications group), 3 had ... high myopia group) and from 30 cataract eyes of 30 patients with no choroidal neovascularization (CNV) or other ocular or ...
Hussain RN, Shahid F, Woodruff G. Axial length in apparently normal pediatric eyes. Eur J Ophthalmol. 2014;24:120-3. [CrossRef] ... Measurement of axial length to monitor progression in eyes with congenital glaucoma. Careful follow-up is very essential for ... Measurement of axial length to monitor progression in eyes with congenital glaucoma ... Measurement of axial length to monitor progression in eyes with congenital glaucoma ...
With respect to parameters, such as axial length of the eye, anterior chamber depth, IOP, or systemic blood pressure, no ... Diurnal axial length fluctuations in human eyes. Invest Ophthalmol Vis Sci. 2004 ; 45: 63-70. ... Diurnal rhythms in intraocular pressure axial length, and choroidal thickness in a primate model of eye growth, the common ... Axial length was measured once before OCT using the Carl Zeiss IOL Master 500 (Carl Zeiss Meditec, Jena, Germany). Blood ...
Eye and Eye (Domestic) - Rope Dia: 1 1/2 in, Length: 8 ft ... The core acts as the axial member about which the strands are ... Domestic - Wire Rope Sling - Eye and Eye - Rope Dia: 1 1/2 in, Length 8 ft ... Eye and Eye - Capacity: 16 to 37 tons. Rope Diameter: 1 1/2 inches. Leg Length: 8 feet ... Domestic - Wire Rope Sling - Eye and Eye - Rope Dia: 1 1/2 in, Length 8 ft ...
... of eyes in which the axial length became shorter than before. Evidence of axial shortening in rhesus macaque (40%) and marmoset ... Axial length was measured with ultrasound biometry in all species. RESULTS: Tree shrew eyes showed a strong trend to shorten ... or is the result of axial elongation of the eye produced by prior negative lens wear or deprivation. This eye shortening ... 30 eyes (88%) shortened, whereas only 7 fellow eyes shortened. In chicks, eyes wearing positive lenses reduced their rate of ...
Axial Length, Eye. publications Timeline , Most Recent This graph shows the total number of publications written about "Organ ...
Axial Length and Refractive Error in Consecutive Pediatric Patients in a Private Optometric Practice. Myopia Management (Ortho- ... The Safety of Orthokeratology Contact Lens Wear in Slowing the Axial Elongation of the Eye in Children. Myopia Management ( ... Corneal topographic and axial length changes after 12 months of customized orthokeratology. Myopia Management (Ortho-K, MF soft ... A Fashionable Eye - A Painted Scleral for a Blind Eye. Scleral lenses Clinical Case Report/Series (optometry resident first ...
Exam using ultrasounds to measure the eye axial length and the depth of the anterior chamber. ... Photograph of external eye parts Photograph of the previous segment performed with a slit lamp, to record clinical cases and ... A vision exam that uses a special lens to study the eye angle of the anterior chamber, where drainage of the aqueous humor is ... Imaging exam that photographs the eye fundus areas, like the retina, the choroid, the optic nerve and the blood vessels. ...
... of total trunk length) and bears a pair of dorsal ovoid structures about 100 μm in length (Figs. 1h and 2h, k-n) interpreted as ... A darker axial structure rich in carbon (Fig. 1c-d; Additional file 6) starting from the distal end of the head and running to ... A, annulations; Bc, basal unit of the claw; C, claw; Ca, compression artifact; Ds, dark stain; E, "eye" (visual organ); G, gut ... The last three pairs of lobopods have strongly curved (c. 150°) claws c. 1 mm in length (Figs. 1e and 2a, b, e). These claws ...
Changes in axial length following trabeculectomy and glaucoma drainage device surgery. Br J Ophthalmol. 2005;89(1):17-20. ... Studies have shown a typical, permanent rise in IOP of approximately 2 mm Hg after cataract surgery in eyes that have ... Additionally, hypotony after filtering surgery can cause the axial length to decrease.8 Further complicating matters, cataract ... and an increase in axial length, with a resultant myopic shift in the final refraction.9 Given these concerns, it is reasonable ...
Extended length eye-to-eye: ~48.5mm. - Compressed length eye-to-eye: ~28.5mm. - Stroke: 20mm. - Spring Length 32mm 14 Turn (0.3 ... Replaces Axial AXI31612 SCX24 shock set. - Reservoir is non-functional. - Mount with wide flange outward to retain O-rings. ...
  • Refractive error and axial length of the eye were followed for 112 children randomized to therapy with the full-power or sham devices. (physiciansweekly.com)
  • Though the difference between groups was significant at 6 months, the effect size in terms of both refractive error and axial length was modest. (physiciansweekly.com)
  • In a multivariate generalized estimating equation model adjusting for correlation between eyes, the coefficient for the effect of full-power therapy on change in refractive error was 0.167 diopters, with a 95% confidence interval of 0.050-0.283 diopters. (physiciansweekly.com)
  • Overview of Refractive Error In the emmetropic (normally refracted) eye, entering light rays are focused on the retina by the cornea and the lens, creating a sharp image that is transmitted to the brain. (msdmanuals.com)
  • More commonly, refractive error is measured with a standard phoropter or an automated refractor (a device that measures changes in light projected and reflected by the patient's eye). (msdmanuals.com)
  • About 109 eyes of 78 pathologic myopia patients without myopic CNV were randomly selected as the control group. (frontiersin.org)
  • Sclera plays a pivotal role in determining eye size and the development of myopia ( 10 ). (frontiersin.org)
  • Called pathological myopia, this is where the length and shape of your eye condition increases over time, ultimately increasing the risk of retinal damage. (naturaleyecare.com)
  • Myopia, which is the result of a mismatch between the axial length (AL) and ocular refractive power, has become a major public health issue worldwide [ 1 ]. (springer.com)
  • Three-year findings indicated that use of the dual-focus contact lens - which has alternating visual correction and treatment zones - was effective in slowing myopia progression: 59% as measured by mean cycloplegic spherical equivalent (SE) and 52% as measured by mean axial elongation of the eye when compared to the children in the control group wearing a single vision 1-day contact lens. (coopervision.com)
  • The presence of disease was high even in individuals with relatively mild to moderate myopia with an axial length of 24mm to 26.5mm. (reviewofoptometry.com)
  • Most notably, individuals with lower choroidal thickness were at higher likelihood of myopic maculopathy even if they had relatively mild to moderate myopia with axial length of 24mm to 26.5mm. (reviewofoptometry.com)
  • Methods A total of 208 right eyes of 208 patients with myopia were enrolled and divided into mild, moderate, high, and extreme myopia groups. (aminer.org)
  • Conclusions We characterized a stepwise and quadrant alteration of retinal microvascular density from mild to extreme myopia, which was more strongly affected by axial elongation, although both AL and SE were meaningful indicators. (aminer.org)
  • Medications such as atropine, given as eye drops, can slow the progression of short- or near-sightedness (myopia) in children, and also reduce elongation of the eyeball due to myopia. (cochrane.org)
  • We aimed to find out whether medications used as eye drops, and special lenses in eyeglasses or contact lenses, can slow the progression of myopia, as well as the elongation of the eyeball. (cochrane.org)
  • Several studies have revealed that mechanical stretching stress due to the elongation of axial length can lead to rupture of the capillary network and attenuation of fibroblasts in the choroidal layer. (reviewofoptometry.com)
  • 4 With greater operator independence than ultrasound and increased accuracy (approximately 0.05 mm), optical biometry has arguably become the gold standard for axial length measurement in ophthalmology over the past 10 years. (crstodayeurope.com)
  • In recent years, in a field of ophthalmology, an optical coherence tomography (OCT), which is an apparatus for capturing a tomographic image of a tissue of an eye to be examined, attracts attention (for example, refer to Japanese Patent Publication No. 2016-55122). (justia.com)
  • Water drinking test influences intraocular pressure, axial length and choroid thickness in normal young adults[J]. Ophthalmology in China, doi: 10.13281/j.cnki.issn.1004-4469.2017.01.008 . (j-bio.net)
  • Changing the axial length of the eyeball. (wikipedia.org)
  • 8 A study investigated whether the increasing rate of nearsightedness in diabetics was due to changes in the lens or the length of the eyeball (axial length). (naturaleyecare.com)
  • In particular, the SLITRK6 protein influences the length of the eyeball (axial length), which affects whether a person will be nearsighted or farsighted, or will have normal vision. (medlineplus.gov)
  • AL is thus an important anatomic parameter for the optics of the eye, determining the refraction. (springer.com)
  • First, ultrasound measures the anatomic axial length of the eye, from the anterior pole to the posterior pole, not the optical axial length along the visual axis. (crstodayeurope.com)
  • The visual axis of the human eye is not identical to the anatomic (or geometric) axis. (crstodayeurope.com)
  • As a result, the optical axis in the typical human eye is tilted approximately 5° horizontally and 1° vertically relative to the anatomic axis. (crstodayeurope.com)
  • Because ultrasound does not depend on patient fixation, it measures the anatomic length of the eye, from the corneal vertex to the posterior pole, rather than the optical length. (crstodayeurope.com)
  • For IOL power calculation, the ophthalmologist must know the distance from the corneal vertex to the fovea, but the anatomic length that ultrasound biometry measures is almost always longer than this distance. (crstodayeurope.com)
  • Roberto Zaldivar, MD, and I showed that, in eyes with axial length greater than 26 mm, the anatomic axial length is a mean 0.8 mm longer than the optical axial length. (crstodayeurope.com)
  • Purpose: To explore the associations between diffuse chorioretinal atrophy (DCA) and age, sex, axial length, spherical equivalent, and best-corrected visual acuity (BCVA) among highly myopic eyes. (mendeley.com)
  • The proportion of DCA significantly increased with longer axial length and worse myopic spherical equivalent. (mendeley.com)
  • Background: To generate and validate a method to estimate axial length estimated (ALest) from spherical equivalent (SE) and corneal curvature [keratometry (K)], and to determine if this ALest can replace actual axial length (ALact) for correcting transverse magnification error in optical coherence tomography angiography (OCTA) images using the Littmann-Bennett formula. (edu.au)
  • Longer wavelength (1.050-1.060 nm) and deep penetrance swept-source OCT (SS-OCT) demonstrates its superiority in myopic eyes as it can provide clear visualization of the sclera and orbital fat tissue in myopes with longer axial lengths ( 7 ). (frontiersin.org)
  • Therefore, eyes evolved in water have a mechanism involving changing the distance between a rigid rounder more refractive lens and the retina using less uniform muscles rather than subtly changing the shape of the lens itself using circularly arranged muscles. (wikipedia.org)
  • Moreover, short-sighted people have longer eyes, which means that the retina is stretched. (cochrane.org)
  • Among the myopic individuals with axial length ≥24mm, thinner choroidal thickness was significantly associated with prevalent myopic maculopathy. (reviewofoptometry.com)
  • Mean change in the axial length of the eye was also significantly lower in the intervention group, again indicating slower myopic progression. (physiciansweekly.com)
  • The ILPS series also includes the ILPS-19 series for applications where a shorter length and smaller diameter body is required and the spring loaded ILPS-18S for applications where the probe cannot be hard fixed to the measurand. (ien.eu)
  • The axial length become shorter, the anterior chamber depth become shallow and the vitreous thickness become shorter, and the lens thickness and the choroid thickness have no significant changes. (j-bio.net)
  • Further, the term primary angle closure suspect refers to an eye in which there is contact between the peripheral iris and the posterior trabecular meshwork, or in which contact is considered possible based on ocular anatomy, and there is no evidence of acute disease. (medscape.com)
  • The characteristics and ocular biometry were compared between participants' eyes with and without DCA. (mendeley.com)
  • Famously, the ocular hypertension treatment study, European glaucoma prevention study, and Barbados eye study showed that CCT could be a risk factor for development and progression of glaucoma disease. (researchsquare.com)
  • Therefore, our findings suggest that choroidal thinning and longer axial length may contribute to the etiology of myopic maculopathy through the choroidal vascular changes and ocular stretching stress," the investigators concluded in their study. (reviewofoptometry.com)
  • To report variation of the axial length (AL) and anterior chamber depth (ACD) among keratoconic (KC) eyes compared to myopic and emmetropic eyes in an African population sample. (org.pk)
  • Abdu M, Gammoh Y, Abd Alla H. Differences in Axial Length and Anterior Chamber Depth among Keratoconic, Myopic and Emmetropic Eyes: Doi: 10.36351/pjo.v39i4.1607. (org.pk)
  • Contact Lens and Anterior Eye. (aston.ac.uk)
  • Refinements of the technology soon allowed measurement of lens thickness, anterior chamber depth, and other parameters in addition to axial length. (crstodayeurope.com)
  • After water drinking 30 min anterior chamber depth shallowed (P=0.04), after water drinking 60 min axial length shortened (P=0.02) and vitreous length thickness shortened (P=0.04). (j-bio.net)
  • An interface is the junction between any two media of different densities and velocities, which, in the eye, include the anterior corneal surface, the aqueous/anterior lens surface, the posterior lens capsule/anterior vitreous, the posterior vitreous/retinal surface, and the choroid/anterior scleral surface. (medscape.com)
  • EQUALITY study participants received a comprehensive eye exam by an optometrist including medical history, visual acuity with walk-in and best correction, refraction, color vision, applanation tonometry, pachymetry, undilated slit lamp anterior segment examination, undilated gonioscopy, and dilated fundus examination. (cdc.gov)
  • Results: Diffuse chorioretinal atrophy was found in 177 (20.6%) eyes. (mendeley.com)
  • OCT and OCTA images of a highly myopic eye with patchy chorioretinal atrophy. (reviewofoptometry.com)
  • In this retrospective study, we included the patients who are going to undergo cataract surgery in Wuhan Aier Eye Hospital (Hubei, province of China) from January to August 2022. (biomedcentral.com)
  • Significant reduction in central corneal thickness (CCT) was observed over a long-time period in primary angle closure eyes. (researchsquare.com)
  • 1-3 When IOLs began to gain popularity later in the 1970s, cataract surgeons adopted ultrasound A-scans to measure the axial length of the eye for IOL power calculation. (crstodayeurope.com)
  • By the 1990s, ultrasound measurement of axial length was accurate to approximately 0.1 mm, reliable, and the de facto gold standard for the calculation of IOL power in cataract surgery. (crstodayeurope.com)
  • This retrospective study reviews the patients with cataract in Wuhan Aier Eye Department from January to August 2022. (biomedcentral.com)
  • Objective To explore intraocular pressure (IOP), axis length and choroid thickness changes in healthy people after water drinking test. (j-bio.net)
  • Their risk of prevalent myopic maculopathy was further increased if they had both lower choroidal thickness and longer axial length of ≥26.5mm. (reviewofoptometry.com)
  • The values of tHOA, SA and coma aberration were the smallest in emmetropic eyes. (biomedcentral.com)
  • Interventions: Postnatal foot lengths (FL) were measured with Vernier digital calliper in millimetres. (bvsalud.org)
  • Aqueous humor is produced by the ciliary body in the posterior chamber of the eye. (medscape.com)
  • Methods: This study included right eyes of 857 bilaterally highly myopic individuals from the ZOC-BHVI Cohort Study. (mendeley.com)
  • Al-Faisal Eye Hospital at Khartoum state of Sudanfrom January 2022 to September 2022. (org.pk)
  • One-hundred and twenty-four eyes of 62 patients were divided into KC group (n =17, eyes=34), myopic group (n=28, eyes=56), and an age/gender matched emmetropic group (n=17, eyes =34). (org.pk)
  • Eighty-eight eyes of 69 consecutive patients with myopic CNV were included in this study. (frontiersin.org)
  • A total of 976 patients (976 eyes) were included, averagely aged 65 years. (biomedcentral.com)
  • If the both eyes of the patients were eligible, data from only the right eye were used to avoid the use of interdependent data between 2 eyes from the same subject. (biomedcentral.com)
  • Patients look at an eye chart 20 ft (6 m) away. (msdmanuals.com)
  • The onset of the ophthalmopathy is in aimed to investigate the prevalence and most cases concomitant with the onset severity of ophthalmopathy in Graves of hyperthyroidism, but eye disease may patients in our area (north-east of the precede or follow hyperthyroidism [ 3 ]. (who.int)
  • This puts the eye at greater risk of eye diseases such as glaucoma, maculopathy and retinal detachment later in life. (cochrane.org)
  • A-scan biometry became more accurate over time, with the addition of gates to take into account changes in the velocity of sound as it travels through the different media in the eye. (crstodayeurope.com)
  • The secondary endpoints are mortality on day 28, in-hospital mortality on day 60, ventilator-free days during the first 60 days and length of ICU stay. (bvsalud.org)
  • Utilization by patient and hospital the average length of stay was 6.0 days. (cdc.gov)
  • Carl Zeiss Meditec, Oberkochen, Germany) was used to obtain the axial length (AL), and horizontal and vertical corneal curvature. (springer.com)
  • An error of 1 mm in axial length measurement yields a refractive surprise of approximately 2.80 D, so an error of 3 mm could mean a surprise of almost 9.00 D. (crstodayeurope.com)
  • We believe, understanding the corneal changes in PAC eyes according to time is crucial since PAC itself and even its treatments can induce changes in various corneal parameters. (researchsquare.com)
  • Visual acuity in each eye is tested as the opposite eye is covered with a solid object (not the patient's fingers, which may separate during testing). (msdmanuals.com)
  • The term dilacerations refers to an abrupt change in the axial inclination or curve in the crown or root of a tooth. (bvsalud.org)
  • At 6 months, 13 children in the therapy group had a decrease in axial length more than 0.05 mm compared to 3 in the sham group. (physiciansweekly.com)
  • The control group generally received a placebo (sham) treatment or single vision eye glasses or contact lenses. (cochrane.org)
  • The present disclosure relates to an ophthalmologic image processing method of processing OCT data of a tissue of an eye to be examined and an OCT apparatus for executing the ophthalmologic image processing method. (justia.com)
  • In this study, we intended to investigate the long-term change of CCT in terms of rate in eyes with primary angle closure (PAC). (researchsquare.com)
  • Zernike polynomial is commonly used to quantitatively evaluate wavefront aberration of the human eye [ 1 ]. (biomedcentral.com)
  • The primary endpoint of the study is the number of ECMO-free days until day 28, defined as the length of time (in days) from successful libration from V-V ECMO to day 28. (bvsalud.org)
  • This cross-sectional study utilized SDOCT data obtained as part of the Eye Care Quality and Accessibility Improvement in the Community (EQUALITY) demonstration telemedicine program. (cdc.gov)
  • SDOCT scans from 269 eyes (148 participants) were included in the analysis. (cdc.gov)
  • Early intervention by parents, in partnership with eye care professionals, is essential the near- and long-term health and well-being of their children. (coopervision.com)
  • Other contact lenses, called orthokeratology, aim to temporarily change the shape of the eye surface and are worn during sleep and removed during the day. (cochrane.org)
  • Several treatments, including special types of lenses in eye glasses as well as contact lenses, may slow the progression of short-sightedness, but their effect is still uncertain and there is insufficient information on the risk of unwanted effects. (cochrane.org)
  • It was first used by Tomes in 1848 1 and refers to an angulation that may occur anywhere along the length of the tooth, that is, its crown, amelocemental junction, along the root, or by only involving the apex of the root 1-2 . (bvsalud.org)
  • Spike height is not only affected by the difference in density as it travels through the eye but also by the angle of incidence, which is determined by the probe orientation to the visual axis. (medscape.com)
  • Generally mammals, birds and reptiles living in air vary their eyes' optical power by subtly and precisely changing the shape of the elastic lens using the ciliary body. (wikipedia.org)
  • Conclusions We found a significant reduction in CCT over a long-time observation period in PAC eyes. (researchsquare.com)
  • Because of this, IOL power calculation formulas dating back to the 1970s have added 200 µm to the measured axial length to make up the difference. (crstodayeurope.com)
  • If one were to consider 1641 m/s at about 0.5 mm, only 0.04 mm would need to be added to the total eye length, which in no way alters the IOL calculation. (medscape.com)
  • The data of one eye of each volunteer were analyzed. (j-bio.net)
  • Sound travels faster through solids than through liquids, an important principle to understand because the eye is composed of both. (medscape.com)
  • We asked children if school year 2003-04 in 12 urban govern- they had suffered from redness of the eyes, ment schools: 4 primary schools, 4 male head pains (headache) or difficulty reading preparatory schools and 4 female prepara- the blackboard at school. (who.int)
  • Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies. (wikipedia.org)
  • As the human eye is not in an ideal sphere, the optical deviation along a certain ray from the perfect spherical wavefront is defined as wavefront aberration. (biomedcentral.com)
  • It also controls (regulates) the growth of the eye after birth. (medlineplus.gov)
  • Main outcome measures: Postnatal foot length in relation to Intra-Uterine Growth Pattern. (bvsalud.org)