Refraction of LIGHT effected by the media of the EYE.
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.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
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)
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 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.
The condition of where images are correctly brought to a focus on the retina.
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.
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)
The use of statistical and mathematical methods to analyze biological observations and phenomena.
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.
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.
Agents that dilate the pupil. They may be either sympathomimetics or parasympatholytics.
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.
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)
A parasympatholytic anticholinergic used solely to obtain mydriasis or cycloplegia.
A condition of an inequality of refractive power of the two eyes.
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)
Artificial implanted lenses.
The distance between the anterior and posterior poles of the eye, measured either by ULTRASONOGRAPHY or by partial coherence interferometry.
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.
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.
A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.
Gas lasers with excited dimers (i.e., excimers) as the active medium. The most commonly used are rare gas monohalides (e.g., argon fluoride, xenon chloride). Their principal emission wavelengths are in the ultraviolet range and depend on the monohalide used (e.g., 193 nm for ArF, 308 nm for Xe Cl). These lasers are operated in pulsed and Q-switched modes and used in photoablative decomposition involving actual removal of tissue. (UMDNS, 2005)
The aperture in the iris through which light passes.
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 series of tests used to assess various functions of the eyes.
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.
A surgical procedure to correct MYOPIA by CORNEAL STROMA subtraction. It involves the use of a microkeratome to make a lamellar dissection of the CORNEA creating a flap with intact CORNEAL EPITHELIUM. After the flap is lifted, the underlying midstroma is reshaped with an EXCIMER LASER and the flap is returned to its original position.
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.
The use of an aberrometer to measure eye tissue imperfections or abnormalities based on the way light passes through the eye which affects the ability of the eye to focus properly.
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).
Processes and properties of the EYE as a whole or of any of its parts.
Infection caused by the protozoan parasite TOXOPLASMA in which there is extensive connective tissue proliferation, the retina surrounding the lesions remains normal, and the ocular media remain clear. Chorioretinitis may be associated with all forms of toxoplasmosis, but is usually a late sequel of congenital toxoplasmosis. The severe ocular lesions in infants may lead to blindness.
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 normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.
Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)
The removal of a cataractous CRYSTALLINE LENS from the eye.
Surgical procedures employed to correct REFRACTIVE ERRORS such as MYOPIA; HYPEROPIA; or ASTIGMATISM. These may involve altering the curvature of the CORNEA; removal or replacement of the CRYSTALLINE LENS; or modification of the SCLERA to change the axial length of the eye.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
The pressure of the fluids in the eye.
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.
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
The absence or restriction of the usual external sensory stimuli to which the individual responds.
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)
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)
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.
Asymmetries in the topography and refractive index of the corneal surface that affect visual acuity.
The front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.
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.
Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. Low vision generally refers to visual disorders that are caused by diseases that cannot be corrected by refraction (e.g., MACULAR DEGENERATION; RETINITIS PIGMENTOSA; DIABETIC RETINOPATHY, etc.).
One of the MUSCARINIC ANTAGONISTS with pharmacologic action similar to ATROPINE and used mainly as an ophthalmic parasympatholytic or mydriatic.
Application of tests and examinations to identify visual defects or vision disorders occurring in specific populations, as in school children, the elderly, etc. It is differentiated from VISION TESTS, which are given to evaluate/measure individual visual performance not related to a specific population.
A form of ocular misalignment characterized by an excessive convergence of the visual axes, resulting in a "cross-eye" appearance. An example of this condition occurs when paralysis of the lateral rectus muscle causes an abnormal inward deviation of one eye on attempted gaze.
Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.
Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.
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 functional superiority and preferential use of one eye over the other. The term is usually applied to superiority in sighting (VISUAL PERCEPTION) or motor task but not difference in VISUAL ACUITY or dysfunction of one of the eyes. Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS.
A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.
Diseases of the cornea.
Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)
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)
Tumors or cancer of the EYE.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
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.
Disorders that feature impairment of eye movements as a primary manifestation of disease. These conditions may be divided into infranuclear, nuclear, and supranuclear disorders. Diseases of the eye muscles or oculomotor cranial nerves (III, IV, and VI) are considered infranuclear. Nuclear disorders are caused by disease of the oculomotor, trochlear, or abducens nuclei in the BRAIN STEM. Supranuclear disorders are produced by dysfunction of higher order sensory and motor systems that control eye movements, including neural networks in the CEREBRAL CORTEX; BASAL GANGLIA; CEREBELLUM; and BRAIN STEM. Ocular torticollis refers to a head tilt that is caused by an ocular misalignment. Opsoclonus refers to rapid, conjugate oscillations of the eyes in multiple directions, which may occur as a parainfectious or paraneoplastic condition (e.g., OPSOCLONUS-MYOCLONUS SYNDROME). (Adams et al., Principles of Neurology, 6th ed, p240)
A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)
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)
Each of the upper and lower folds of SKIN which cover the EYE when closed.
A condition in which the ocular image of an object as seen by one eye differs in size and shape from that seen by the other.
Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.
Measurements of the height, weight, length, area, etc., of the human and animal body or its parts.
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).
The turning inward of the lines of sight toward each other.
Tuberculous infection of the eye, primarily the iris, ciliary body, and choroid.
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.
Disorder occurring in the central or peripheral area of the cornea. The usual degree of transparency becomes relatively opaque.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
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 fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.
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.
A state in southeastern Australia. Its capital is Sydney. It was discovered by Captain Cook in 1770 and first settled at Botany Bay by marines and convicts in 1788. It was named by Captain Cook who thought its coastline resembled that of South Wales. (From Webster's New Geographical Dictionary, 1988, p840 & Room, Brewer's Dictionary of Names, 1992, p377)
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.
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.
A surgical technique to correct REFRACTIVE ERRORS of the EYE, such as MYOPIA and ASTIGMATISM. In this method, a flap of CORNEAL EPITHELIUM is created by exposure of the area to dilute alcohol. The flap is lifted and then replaced after laser ablation of the subepithelial CORNEA.
Surgical removal of a section of the iris.
Abnormal protrusion of both eyes; may be caused by endocrine gland malfunction, malignancy, injury, or paralysis of the extrinsic muscles of the eye.
Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.
Surgery performed on the eye or any of its parts.
Persons with loss of vision such that there is an impact on activities of daily living.
Partial or total replacement of all layers of a central portion of the cornea.
Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.
Individuals whose ancestral origins are in the southeastern and eastern areas of the Asian continent.
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)
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.
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.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
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)
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.
Inflammation of part or all of the uvea, the middle (vascular) tunic of the eye, and commonly involving the other tunics (sclera and cornea, and the retina). (Dorland, 27th ed)
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 form of ocular misalignment where the visual axes diverge inappropriately. For example, medial rectus muscle weakness may produce this condition as the affected eye will deviate laterally upon attempted forward gaze. An exotropia occurs due to the relatively unopposed force exerted on the eye by the lateral rectus muscle, which pulls the eye in an outward direction.
The blending of separate images seen by each eye into one composite image.
The only family of the order SCANDENTIA, variously included in the order Insectivora or in the order Primates, and often in the order Microscelidea, consisting of five genera. They are TUPAIA, Ananthana (Indian tree shrew), Dendrogale (small smooth-tailed tree shrew), Urogale (Mindanao tree shrew), and Ptilocercus (pen-tailed tree shrew). The tree shrews inhabit the forest areas of eastern Asia from India and southwestern China to Borneo and the Philippines.
Abnormally low intraocular pressure often related to chronic inflammation (uveitis).
Surgical techniques on the CORNEA employing LASERS, especially for reshaping the CORNEA to correct REFRACTIVE ERRORS.
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.
A potent, long-acting cholinesterase inhibitor used as a miotic in the treatment of glaucoma.
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.
Absence of the crystalline lens resulting from cataract extraction.
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.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
Images seen by one eye.
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.
A procedure to surgically correct REFRACTIVE ERRORS by cutting radial slits into the CORNEA to change its refractive properties.
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.
Diseases affecting the eye.
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)
Lenses, generally made of plastic or silicone, that are implanted into the eye in front of the natural EYE LENS, by the IRIS, to improve VISION, OCULAR. These intraocular lenses are used to supplement the natural lens instead of replacing it.
The lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes.
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.
Congenital absence of or defects in structures of the eye; may also be hereditary.
The period following a surgical operation.
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.
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.
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.
A genus of the subfamily CALLITRICHINAE occurring in forests of Brazil and Bolivia and containing seventeen species.
Measurement of the thickness of the CORNEA.
A superorder in the class CEPHALOPODA, consisting of the orders Octopoda (octopus) with over 200 species and Vampyromorpha with a single species. The latter is a phylogenetic relic but holds the key to the origins of Octopoda.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
Application of pharmaceutically active agents on the tissues of the EYE.
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.
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.
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.
Filarial infection of the eyes transmitted from person to person by bites of Onchocerca volvulus-infected black flies. The microfilariae of Onchocerca are thus deposited beneath the skin. They migrate through various tissues including the eye. Those persons infected have impaired vision and up to 20% are blind. The incidence of eye lesions has been reported to be as high as 30% in Central America and parts of Africa.
A chronic blistering disease with predilection for mucous membranes and less frequently the skin, and with a tendency to scarring. It is sometimes called ocular pemphigoid because of conjunctival mucous membrane involvement.
Techniques for securing together the edges of a wound, with loops of thread or similar materials (SUTURES).
Disorders affecting TWINS, one or both, at any age.
Introduction of substances into the body using a needle and syringe.
Inflammation of the choroid in which the sensory retina becomes edematous and opaque. The inflammatory cells and exudate may burst through the sensory retina to cloud the vitreous body.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
Elements of limited time intervals, contributing to particular results or situations.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.
Inflammation of the cornea.
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.
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.
Methods of creating machines and devices.
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
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.
Inflammation of the eyelids.
A country spanning from central Asia to the Pacific Ocean.
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.
Refers to any inflammation of the sclera including episcleritis, a benign condition affecting only the episclera, which is generally short-lived and easily treated. Classic scleritis, on the other hand, affects deeper tissue and is characterized by higher rates of visual acuity loss and even mortality, particularly in necrotizing form. Its characteristic symptom is severe and general head pain. Scleritis has also been associated with systemic collagen disease. Etiology is unknown but is thought to involve a local immune response. Treatment is difficult and includes administration of anti-inflammatory and immunosuppressive agents such as corticosteroids. Inflammation of the sclera may also be secondary to inflammation of adjacent tissues, such as the conjunctiva.
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.
The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.
A beta-adrenergic antagonist similar in action to PROPRANOLOL. The levo-isomer is the more active. Timolol has been proposed as an antihypertensive, antiarrhythmic, antiangina, and antiglaucoma agent. It is also used in the treatment of MIGRAINE DISORDERS and tremor.
A superficial, epithelial Herpesvirus hominis infection of the cornea, characterized by the presence of small vesicles which may break down and coalesce to form dendritic ulcers (KERATITIS, DENDRITIC). (Dictionary of Visual Science, 3d ed)
An ethnic group with historical ties to the land of ISRAEL and the religion of JUDAISM.
Tongues of skin and subcutaneous tissue, sometimes including muscle, cut away from the underlying parts but often still attached at one end. They retain their own microvasculature which is also transferred to the new site. They are often used in plastic surgery for filling a defect in a neighboring region.

Latrunculin-A causes mydriasis and cycloplegia in the cynomolgus monkey. (1/981)

PURPOSE: To determine the effect of latrunculin (LAT)-A, which binds to G-actin and disassembles actin filaments, on the pupil, accommodation, and isolated ciliary muscle (CM) contraction in monkeys. METHODS: Pupil diameter (vernier calipers) and refraction (coincidence refractometry) were measured every 15 minutes from 0.75 to 3.5 hours after topical LAT-A 42 microg (approximately 10 microM in the anterior chamber [AC]). Refraction was measured every 5 minutes from 0.5 to 1.5 hours after intracameral injection of 10 microl of 50 microM LAT-A (approximately 5 microM in AC), with intramuscular infusion of 1.5 mg/kg pilocarpine HCl (PILO) during the first 15 minutes of measurements. Pupil diameter was measured at 1 and 2 hours, and refraction was measured every 5 minutes from 1 to 2 hours, after intravitreal injection of 20 microl of 1.25 mM LAT-A (approximately 10 microM in vitreous), with intramuscular infusion of 1.5 mg/kg PILO during the first 15 minutes of measurements (all after topical 2.5% phenylephrine), and contractile response of isolated CM strips, obtained <1 hour postmortem and mounted in a perfusion apparatus, to 10 microM PILO +/- LAT-A was measured at various concentrations. RESULTS: Topical LAT-A of 42 microg dilated the pupil without affecting refraction. Intracameral LAT-A of 5 microM inhibited miotic and accommodative responses to intramuscular PILO. Intravitreal LAT-A of 10 microM had no effect on accommodative or miotic responses to intramuscular PILO. LAT-A dose-dependently relaxed the PILO-contracted CM by up to 50% at 3 microM in both the longitudinal and circular vectors. CONCLUSIONS: In monkeys, LAT-A causes mydriasis and cycloplegia, perhaps related to its known ability to disrupt the actin microfilament network and consequently to affect cell contractility and adhesion. Effects of LAT-A on the iris and CM may have significant physiological and clinical implications.  (+info)

Reflective meniscometry: a non-invasive method to measure tear meniscus curvature. (2/981)

AIMS: To devise a method to measure tear meniscus curvature by a non-invasive specular technique. METHODS: A photographic system was devised. The system consisted of a camera and an illuminated target with a series of black and white stripes oriented parallel to the axis of the lower tear meniscus. The target was mounted on a flash gun close to the objective of a Brown macrocamera and calibrated using a graduated series of glass capillaries of known diameter, ground down to expose the inner wall. It was then applied to normal human eyes (n = 45) to measure the tear meniscus curvature. A video system was also assessed which provided qualitative online information about the tear meniscus. RESULTS: Using the photographic system, measured values for capillary radii were in excellent agreement with theoretical calculations (r2 = 0.996, p < 0.0001). The radii of curvature of lower tear menisci in normal human subjects (mean 0.365 (SD 0.153) mm, range 0.128-0.736; n = 45) were similar to those reported in the literature. Both systems demonstrated variations in meniscus shape. The video system provided stable images of human menisci over prolonged periods of time and promises to be useful for the analysis of dynamic changes in meniscus volume. CONCLUSIONS: Reflective meniscometry is a non-invasive technique providing quantitative information about tear meniscus shape and volume and of potential value in the study of ocular surface disease.  (+info)

Normal development of refractive state and ocular component dimensions in the marmoset (Callithrix jacchus). (3/981)

Refractive state and ocular dimensions were studied longitudinally in nine normal marmosets. Animals were anaesthetised and examined (with some exceptions) at 4, 6, 7, 8, 10, 15, 24 and 39 weeks of age. Cycloplegic retinoscopy showed that hyperopia early in life rapidly diminished. Refraction corrected for the artefact of retinoscopy stabilised by 8 weeks of age, but at a slightly myopic value, rather than at emmetropia. The ocular components continued to change throughout the period studied. Corneal radius, measured by photokeratometry, increased slightly during development. Anterior segment depth and vitreous chamber depth (VCD), measured by A-scan ultrasonography, increased throughout development while lens thickness initially increased and then decreased. Data from the eyes of these normal animals were compared with that from the contralateral eyes of animals which received short periods of monocular deprivation early in life (Troilo, D., & Judge S.J. (1993). Ocular development and visual deprivation myopia in the common marmoset (Callithrix jacchus jacchus). Vision Research, 33, 1311-24); eyes which viewed through no lens or a plano lens (Graham, B. & Judge, S.J. (1999)). The effects of spectacle wear in infancy on eye growth and refractive error in the marmoset (Callithrix jacchus). Vision Research, 39, 189-206), and eyes of normal animals in another colony. There were no significant differences between the first two groups and the normal animals in our colony while age-matched animals from the other colony were slightly but significantly less myopic than our animals.  (+info)

Biometric, optical and physical changes in the isolated human crystalline lens with age in relation to presbyopia. (4/981)

The biometric, optical and physical properties of 19 pairs of isolated human eye-bank lenses ranging in age from 5 to 96 years were compared. Lens focal length and spherical aberration were measured using a scanning laser apparatus, lens thickness and the lens surface curvatures were measured by digitizing the lens profiles and equivalent refractive indices were calculated for each lens using this data. The second lens from each donor was used to measure resistance to physical deformation by providing a compressive force to the lens. The lens capsule was then removed from each lens and each measurement was repeated to ascertain what role the capsule plays in determining these optical and physical characteristics. Age dependent changes in lens focal length, lens surface curvatures and lens resistance to physical deformation are described. Isolated lens focal length was found to be significantly linearly correlated with both the anterior and posterior surface curvatures. No age dependent change in equivalent refractive index of the isolated lens was found. Although decapsulating human lenses causes similar changes in focal length to that which we have shown to occur when human lenses are mechanically stretched into an unaccommodated state, the effects are due to nonsystematic changes in lens curvatures. These studies reinforce the conclusion that lens hardening must be considered as an important factor in the development of presbyopia, that age changes in the human lens are not limited to the loss of accommodation that characterizes presbyopia but that the lens optical and physical properties change substantially with age in a complex manner.  (+info)

The growing eye: an autofocus system that works on very poor images. (5/981)

It is unknown which retinal image features are analyzed to control axial eye growth and refractive development. On the other hand, identification of these features is fundamental for the understanding of visually acquired refractive errors. Cyclopleged chicks were individually kept in the center of a drum with only one viewing distance possible. Defocusing spectacle lenses were used to stimulate the retina with defined defocus of similar magnitude but different sign. If spatial frequency content and contrast were the only cues analyzed by the retina, all chicks should have become myopic. However, compensatory eye growth was still always in the right direction. The most likely cues for emmetropization, spatial frequency content and image contrast, do therefore not correlate with the elongation of the eye. Rather, the sign of defocus was extracted even from very poor images.  (+info)

The refractive development of untreated eyes of rhesus monkeys varies according to the treatment received by their fellow eyes. (6/981)

To determine the extent to which the visual experience of one eye may influence the refractive development of its fellow eye, we analyzed the data of untreated (UT) eyes of monkeys that received different types of unilateral pattern deprivation. Subjects were 15 juvenile rhesus monkeys, with five monkeys in each of three treatment groups: aphakic eyes with optical correction (AC), aphakic eyes with no correction (ANC), and eyes that were occluded with an opaque contact lens (OC). Under general anaesthesia, refractive error (D) was determined by cycloplegic retinoscopy and axial length (mm) was determined with A-scan ultrasonography. For measurements of refractive error of the UT eyes, there was a significant main effect of groups according to the treatment of the fellow eyes, F(2, 12) = 6.6. While UT eyes paired with AC fellow eyes (mean = +4.2 D) were significantly more hyperopic than the eyes of age-matched normal monkeys (mean = +2.4 D), t(25), = 2.5, UT eyes paired with OC fellow eyes (mean = -0.5 D) were significantly more myopic than the eyes of normal monkeys, t(25) = -9. UT eyes paired with ANC fellow eyes (mean = +1.9 D) were not significantly different from normal eyes. For measurements of axial length there was also a significant main effect of groups, F(2, 12) = 6.9. While UT eyes paired with AC fellow eyes (mean = 16.9 mm) were significantly shorter than the eyes of age-matched normal monkeys (mean = 17.5 mm), t(25) = 2.3, UT eyes paired with OC fellow eyes (mean = 18.1 mm) were significantly longer than the eyes of normal monkeys, t(25) = 2.3. UT eyes paired with ANC fellow eyes (mean = 17.5 mm) were not significantly different from the eyes of normal monkeys. The measurements of axial length and of refractive error of the UT eyes were also significantly correlated with one another, probably indicating that the differences in refractive error were due to differences in axial length, r = -0.8. The present data reveal that despite normal visual experience, UT eyes can have their refractive development altered, systematically, simply as a function of the type of pattern deprivation received by their fellow eyes. These data add to the growing evidence that there is an interocular mechanism that is active during emmetropization. As a consequence, future models of eye growth will need to consider both: (1) the direct influence of visual input on the growing eye; as well as (2) the indirect influence coming from the fellow eye.  (+info)

Changes in corneal wavefront aberrations with aging. (7/981)

PURPOSE: To investigate whether corneal wavefront aberrations vary with aging. METHODS: One hundred two eyes of 102 normal subjects were evaluated with videokeratography. The data were decomposed using Taylor and Zernike polynomials to calculate the monochromatic aberrations of the cornea for both small (3-mm) and large (7-mm) pupils. RESULTS: For a 3-mm pupil, the amount of total aberrations (Spearman rank correlation coefficient r(s) = 0.145; P = 0.103) and spherical-like aberrations (r(s) = -0.068; P = 0.448) did not change with aging, whereas comalike aberrations exhibited a weak but statistically significant correlation with age (r(s) = 0.256; P = 0.004). For a 7-mm pupil, total aberrations (r(s) = 0.552; P < 0.001) and comalike aberrations (r(s) = 0.561; P < 0.001) significantly increased with aging, but spherical-like aberrations showed no age-related changes (r(s) = 0.124; P = 0.166). Simulated pupillary dilation from 3 mm to 7 mm caused a 38.0+/-28.5-fold increase in the total aberrations, and the extent of increases significantly correlated with age (r(s) = 0.354; P < 0.001). Pupillary dilation influenced the comalike aberrations more in the older subjects than in the younger subjects (r(s) = 0.243; P = 0.006), but such age dependence was not found for spherical-like aberrations (r(s) = 0.141; P = 0.115). CONCLUSIONS: Comalike aberrations of the cornea correlate with age, implying that the corneas become less symmetrical along with aging. Spherical-like aberrations do not vary significantly with aging. Pupillary dilation markedly increases wavefront aberrations, and those effects are more prominent in older subjects than in younger subjects.  (+info)

Spherical and aspherical photorefractive keratectomy and laser in-situ keratomileusis for moderate to high myopia: two prospective, randomized clinical trials. Summit technology PRK-LASIK study group. (8/981)

OBJECTIVE: Determine the outcomes of single-zone photorefractive keratectomy (SZPRK), aspherical photorefractive keratectomy (ASPRK), and laser in-situ keratomileusis (LASIK) for the correction of myopia between -6 and -12 diopters. DESIGN: Two simultaneous prospective, randomized, multi-center clinical trials. PARTICIPANTS: 286 first-treated eyes of 286 patients enrolled in one of two studies. In Study I, 134 eyes were randomized to SZPRK (58 eyes) or ASPRK (76 eyes). In Study II, 152 eyes were randomized to ASPRK (76 eyes) or to LASIK (76 eyes). INTERVENTION: All eyes received spherical one-pass excimer laser ablation as part of PRK or LASIK performed with the Summit Technologies Apex laser under an investigational device exemption, with attempted corrections between -6 and -12 diopters. MAIN OUTCOME MEASURES: Data on uncorrected and best spectacle-corrected visual acuity, predictability and stability of refraction, and complications were analyzed. Follow-up was 12 months. RESULTS: At 1 month postoperatively, more eyes in the LASIK group achieved 20/20 and 20/25 or better uncorrected visual acuity than PRK-treated eyes; at the 20/25 or better level, the difference was significant for LASIK (29/76 eyes, 38%) over SZPRK (10/58 eyes, 17%) (P = .0064). At all subsequent postoperative intervals, no difference was seen between treatment groups. Similarly, best corrected visual acuities were better for LASIK than all PRK eyes at 1 month postoperatively, and LASIK was better than SZPRK at 3 months follow-up (e.g., for 20/20 or better at 1 month, LASIK 50/76 eyes (66%) versus SZPRK 24/57 eyes (42%), P = .0066). PRK eyes had a mean loss of BCVA through 6 months, while LASIK eyes had a slight gain of mean BCVA through month 6; at 12 months, both ASPRK groups but not SZPRK continued to have a small mean loss of BCVA (e.g., compared to preoperative, mean BCVA at 12 months for SZPRK was + 0.3, LASIK was +.21, ASPRK I was -0.11, and ASPRK II -0.31 (SZPRK versus ASPRK II, P = .0116). Predictability was better for PRK than LASIK at all follow-up intervals (e.g., for manifest refraction spherical equivalent +/- 1.0 diopters at 6 months, ASPRK I 42/62 eyes (68%) versus LASIK 29/72 eyes (40%), P = .0014%). Stability was slightly but insignificantly less in the LASIK eyes compared to PRK eyes. All visual outcome measures were better for eyes with preoperative myopia between -6 and -8.9 D compared with eyes with myopia between -9 and -12 D. No consistent differences in refractive outcomes or postoperative corneal haze were seen between aspherical and single-zone ablations; haze diminished over 12 months and was judged to be vision-impairing in only one ASPRK eye. Microkeratome and flap complications occurred in 4 eyes, resulting in delay of completion of the procedure in 3 eyes but not causing long-term impairment. CONCLUSIONS: Improvement in uncorrected visual acuity and return of best corrected visual acuity was more rapid for LASIK than PRK, but efficacy outcomes in the longer term through 12 months were similar for all treatment groups. LASIK eyes tended toward undercorrection with the nomogram employed in this study compared to PRK, but the scatter was similar, suggesting little difference between these procedures for most patients by 6 months and thereafter. No consistent advantage was demonstrated between aspherical and single-zone ablation patterns. Predictability was much better for all procedures for corrections of -6 to -8.9 D compared with -9 to -12 D. Sporadic loss of best corrected vision in the PRK eyes not found in the LASIK eyes and other measures of visual function require further study.  (+info)

In another study, Atchison et al. 30 measured peripheral refraction out to 35° eccentricity in horizontal and vertical meridians of emmetropic and myopic subjects up to −12 D. Relative hyperopic and myopic shifts were reported in horizontal and vertical meridians, respectively, in the myopic group. Moreover, J 180 was found to increase negatively in horizontal, and positively in vertical meridians, relative to the fovea. In addition, Atchison et al. showed that the differences in peripheral refraction between myopic and emmetropic eyes are small when measured along the vertical meridian out to 30° eccentricity compared with those measured along the horizontal meridian. Figure 8 illustrates the comparison of our results with those in previous peripheral refraction studies on the horizontal and vertical meridians. Our data illustrate a relative hyperopic shift which was similar for all measured meridians for the myopic group, and a relatively constant refractive profile for emmetropic eyes ...
Purpose: To compare the mean difference of visual acuity as measured by auto refraction and subjective refraction.. Study Design: Descriptive cross-sectional study.. Place and Duration of Study: Department of ophthalmology, Services hospital Lahore from November 2013 to April 2014.. Material and Methods: Using non-probability consecutive sampling 300 eyes of 300 patients fulfilling inclusion criteria were recruited through OPD registration slip. Demographic data including age and gender was recorded. Complete ophthalmic examination was performed. This included measurement of refractive error by auto-refraction as well as subjective refraction. Detailed anterior segment examination with slit lamp and dilated fundus examination with indirect ophthalmoscopy was performed. The collected data was analyzed by using software SPSS version 17.. Results: The mean age of patients was 34.71 ± 7.45 years. There were 156 (52%) males and 144 (48%) females. There were 263 (87.69%) patients who had visual ...
An apparatus for determining the objective refraction of a patients eye includes a transparent window and a wavefront measurement device that determines aberrations in a return beam from the patients eye after the beam passes through a corrective test lens in the apparatus. The wavefront measurement device outputs an instant display representative of the quality of vision afforded the patient through the test lens. The display can be a representation of a Snellen chart, convoluted with the optical characteristics of the patients vision, an overall quality of vision scale or the optical contrast function, all based on the wavefront measurements of the patients eye. The examiner may use the display information to conduct a refraction examination and other vision tests without the subjective response from the patient.
Illumination was from three different types of LED light tubes (Shanghai Rui Gao Xiang Light and Electronic Corporation, Shanghai, China): blue (λmax = 430 nm, half-bandwidth = 20 nm), green (λmax = 530 nm, half-bandwidth = 30 nm), and white (color temperature = 5000 K). The blue and green LEDs were chosen based on the spectral sensitivity of the S-cone system (429 nm) and the M-cone system (529 nm) of the guinea pig (Jacobs & Deegan, 1994). Data from the manufacturer indicated that the white light had no bias toward the blue or green and perfectly covered the output of the two monochromatic sources. The illumination conditions and housing were designed as previously described (Liu et al., 2011). Four to six LED tubes were placed on each interior surface (including the ceiling and floor) of specially designed wooden crates with white paint on the inner walls to ensure homogenous illumination. Guinea pigs were reared in cages (dimensions: 80.0 × 50.0 × 40.0 cm, mesh size: 1.5 × 5.0 cm2) that ...
Looking for absolute index of refraction? Find out information about absolute index of refraction. index of refraction Explanation of absolute index of refraction
An image capturing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The second lens element has negative refractive power. The third lens element has refractive power. The fourth lens element has refractive power. The fifth lens element with refractive power has an object-side surface and an image-side surface being both aspheric, wherein at least one surface of the fifth lens element has at least one inflection point. The sixth lens element with positive refractive power has an image-side surface being convex in a paraxial region thereof, wherein the surfaces of the sixth lens element are aspheric. The image capturing lens assembly has a total of six lens elements with refractive power. When specific conditions are
The diagram on the right shows an example of refraction in water waves. Ripples travel from the left and pass over a shallower region inclined at an angle to the wavefront. The waves travel slower in the more shallow water, so the wavelength decreases and the wave bends at the boundary. The dotted line represents the normal to the boundary. The dashed line represents the original direction of the waves. This phenomenon explains why waves on a shoreline tend to strike the shore close to a perpendicular angle. As the waves travel from deep water into shallower water near the shore, they are refracted from their original direction of travel to an angle more normal to the shoreline.[3] Refraction is also responsible for rainbows and for the splitting of white light into a rainbow-spectrum as it passes through a glass prism. Glass has a higher refractive index than air. When a beam of white light passes from air into a material having an index of refraction that varies with frequency, a phenomenon ...
Glycerol is a clear, colorless, and sweet-tasting, viscous liquid also frequently referred to as glycerin or glycerine. It is also less commonly known as 1,2,3-propanetriol, 1,2,3-trihydroxypropane, or glycol alcohol. Glycerol belongs to the alcohol family in organic compounds and contains three hydroxyl groups (-OH). The chemical formula of glycerol is C3H8O3 and the molecular formula is HOCH2CHOHCH2OH. Glycerol is a common substance found in soap, cosmetics, creams, and foods as well as being used in chemical studies and experiments.. Refraction is the change in angle of light when moving from one medium into another. The index of refraction, n, can be determined by c/v where c is the approximate speed of light, 3 × 108 m/s, and v is the phase velocity, or the speed inside the medium. However, the refractive index is also defined as a constant that is the ratio of the sine of the angle of incidence to the sine of the angle of refraction. This application is used in Snells Law, given as: n1 ...
D5777 - 00(2011)e1 Standard Guide for Using the Seismic Refraction Method for Subsurface Investigation , Archeological investigations, Field testing--soil, Geological investigations, Geophysical investigations/geophysics, Hydrogeologic models/investigations, Mineral exploration, Petroleum exploration, Refraction, Seismic refraction, Subsurface investigation--soil/rock, Surface analysis--soil/rock/related materials,
Precise. In the traditional refraction procedure, values are rounded to 0.25 D at each stage and inaccuracies accumulate. In the precise Digital Infinite Refraction™ procedure, all the refraction is conducted with 0.01 D increments and the final value is rounded to the nearest 0.25 D, with four options for the optometrist to choose from, providing a more reliable result for your patient.. Patient comfort. The smooth power changes and a wider field of vision make refraction very comfortable for the patient. The procedure is shorter and there is no fatigue. All along the refraction procedure, variation steps are adjusted to patient sensitivity making differences easier to perceive and, as a consequence, responses are easier to give. At the end of the test, Vision-R 800 phoropter offers patients the fascinating experience of comparing refractions in simulated real-life conditions.. Easier for the Optometrist. The practitioner reaches the final refraction more quickly than with traditional methods ...
When adjusting the lens, both your refractive power and any astigmatism that may occur can be corrected: If the refractive power of the lens needs to be increased, the physician irradiates the central part of the Light Adjustable Lens with UV light. This will make the lens thicker in the center. The refractive power increases.. If the refractive power of the lens is too high, the edges of the Light Adjustable Lens (LAL) are irradiated instead of the middle. The center of the lens flattens and the refractive power is reduced. Astigmatism can also be corrected in the same way. Undesirable changes in the lens caused by the UV light from your environment must be excluded. To avoid this risk, you will be given UV protection goggles, which will be worn from the operation until the final fixation of the lens. After adjusting the lens, the fixation of your lens takes place. For this we also use the LDD device. The lens can not change anymore. Enjoy now the look you want to measure.. ...
Refraction. Computer artwork showing the refraction of light beams through a biconcave lens. Light changes direction, or is refracted, when it meets a different transparent medium such as a lens. A biconcave lens causes light beams to diverge. It is used to correct myopia (short- sightedness), a condition in which light is focused before it reaches the retina. - Stock Image A205/0081
A process is disclosed for fabricating an improved antireflection coating on a substrate. A layer of dielectric material having a first thickness and a first index of refraction are formed overlying a substrate. The dielectric material is implanted with hydrogen to form an implanted surface region having a thickness less than the thickness of the entire layer of dielectric material. The hydrogen reduces the index of refraction of the implanted region to a value less than the index of refraction of the initial layer. The structure overlying the substrate thus includes two integral layers having different indices of refraction with the lower index of refraction, as desired, at the surface of the dielectric material. The process can be extended by further implantation to provide an increased number of distinct layers of differing index or to provide a continuum of regions of varying index of refraction.
The availability of the products differs from country to country depending on the status of approval in each country. Specifications and design are subject to change without notice.. ...
Methods 180 children (150 former prematures and 30 age-matched term-born children) were enrolled at age 6-13 years. Former prematures were categorised by the results of the initial ROP screening based on digital wide-field fundus imaging: absence of ROP (n=100) and spontaneously resolved ROP (n=50). The latter group was further subdivided according to their STG (Stg 1; Stg 2; Stg 3). Both groups were categorised into sectors by BW (,1000 g; 1000-1500 g; ,1500 g), and GA (≤28 weeks; ,28,32 weeks; ≥32 weeks). VA was assessed with Early Treatment of Diabetic Retinopathy Study letters, LIS was measured at 0°, 2.8° and 8° in the visual field (Microperimeter MP1, Nidek Technologies), and spherical equivalent refraction assessed with a Nidek autorefractor (Nidek, Italy). ...
Packaged semiconductor light emitting device are provided including a reflector having a lower sidewall portion defining a reflective cavity. A light emitting device is positioned in the reflective cavity. A first quantity of cured encapsulant material having a first index of refraction is provided in the reflective cavity including the light emitting device. A second quantity of cured encapsulant material having a second index of refraction, different from the first index of refraction, is provided on the first quantity of cured encapsulant material. The first and second index of refraction are selected to provide a buried lens in the reflective cavity.
A multilayered structure of metal and dielectric thin-films has a cylindrical dispersion surface for TM polarized light. Refraction and diffraction of the light wave in a metal/dielectric multilayered prism has been investigated.. © 2006 Optical Society of America. PDF Article ...
The indices of refraction of potassium pentaborate, KB5O8·4H2O, have been measured over a range of wavelengths and the results fitted to a Sellmeier equation. No indication of an approaching absorption edge is found in transmission measurements from 0.56 to 0.20 μ.. © 1976 Optical Society of America. Full Article , PDF Article ...
Compare risks and benefits of common medications used for Refraction, Assessment. Find the most popular drugs, view ratings, user reviews, and more...
Reflection and refraction are two of the ways light interacts with matter, with absorption being the third. Reflection occurs when incoming light is bounced off of a surface. Reflection can be either...
Refraction is the change in direction of a wave caused by a change in speed as the wave passes from one medium to another. Snells law explains this change.
Posts about refraction in chromosomes written by Irene Caesar, Ph.D. / Ирина Цезарь, Доктор Философских Наук
The other day a friend of mine came in for an eye exam. The exam went smooth, a new prescription for glasses was issued but when we dispensed them to her a few days later, things just seemed off. Although things looked clear, her eyes felt strained, something wasnt quite right. We checked the prescription…
18. US Patent 5,750,143, May 12, 1998. Вв Matrix effects may be due to hemolysis, lipemia, ionic strength differences, pH, serum proteins such as complement or rheumatoid factor, anticoagulants, binding proteins, autoantibodies or heterophilic anti-IgG antibodies. Pharm.
a. is a contact lens b. gives a minified view of the retina c. forms a real inverted image. d. used with concave surface towards patient e. works by neutralizing the refractive power of the eye ...
The Canon RK-5 Autorefractor Keratometer combines refraction and keratometery readings in one compact, efficient unit with wide measurement range. The RK-5 can be utilized to document lens opacity (retinal illumination), and PD.. ...
To determine the causes of any vision change reported during pregnancy. An obstetrical practice in Southampton, New York. Two hundred forty pregnant women were asked whether they had any alteration in
Encourage students to discuss why they believe the prism is altering the method by which the pattern looks. This report deals with these topics concerning the dispersion of light by means of a prism. The easiest way to explain dispersion is by way of dispersion in the prism. To discover refractive index of distinct liquids utilizing hollow prism.. paper writing helper That would be based on the size of the prisms. Rainbows are made by a mixture of refraction and reflection. We are aware that the index of refraction n is dependent on the medium. Because of this simple fact the prism is utilized in periscope fig. 14. To begin with, a normal prism is a prism with frequent polygon bases.. Combining terms, clearly, leads to even more restricted exceptional situations, for example, a right, regular prism. Engineers need a complete comprehension of wave properties in order to design safe and effective products! Choose an ideal equation.. essay topics Most kinematics problems you are going to be ...
a. it has the same refractive index as silicone b. it can be used to make foldable lens c. it increases in size with hydration d. it is more susceptible to damage from YAG laser ...
The change in direction of a wave caused by its change in velocity, as it moves from one medium into another. When a wave passes into a slower medium at an angle, you can imagine one end of the wavefront being slowed down first, which bends the wave into a new direction.. ...
Add footnotes describing issues noted in the main list here. [1]: Does not work at high zoom when refraction corrections are enabled. Possibly because the RefractCorr1 array is not the exact inverse map of RefractCorr2 array. The bug is in objectNearest and thus other features are affected too. [2]: Tracking at high zoom sometimes shakes the display periodically. This has nothing to do with atmospheric refraction. [3]: FIXED [897451]The clock is paused if it is running, but the icon in the toolbar doesnt change state [4]: The display in the status bar shows a different field of view (possibly the minor axis) from what is entered [5]: Why are there 2 Main Toolbars? Is this a bug that only I am experiencing? [6]: What are those blank actions? [7]: TODO: Check if the altitude / azimuth shown are the real altitude and azimuth and not the back-refracted ones. [8]: Disable / dont show the faint magnitude zoomed in / zoomed out spin boxes under the catalogs tab [9]: CANT FIX BEFORE 4.2 DUE TO ...
Add footnotes describing issues noted in the main list here. [1]: Does not work at high zoom when refraction corrections are enabled. Possibly because the RefractCorr1 array is not the exact inverse map of RefractCorr2 array. The bug is in objectNearest and thus other features are affected too. [2]: Tracking at high zoom sometimes shakes the display periodically. This has nothing to do with atmospheric refraction. [3]: FIXED [897451]The clock is paused if it is running, but the icon in the toolbar doesnt change state [4]: The display in the status bar shows a different field of view (possibly the minor axis) from what is entered [5]: Why are there 2 Main Toolbars? Is this a bug that only I am experiencing? [6]: What are those blank actions? [7]: TODO: Check if the altitude / azimuth shown are the real altitude and azimuth and not the back-refracted ones. [8]: Disable / dont show the faint magnitude zoomed in / zoomed out spin boxes under the catalogs tab [9]: A lot of widgets have ...
CSTs simulation software provides accurate 3D electromagnetic EDA solutions for the numerical solution of Maxwells Equations, from statics up to highest frequencies.
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There is also no point keflex pt copii pret considering that what- ever happens cтpii however little QC is carried out, QA will discover all the mistakes in the final report and review. The disease tends prett progress rapidly and does not respond well to treatment.
A new generation of premium lenses promises to offer opportunities for increasingly accurate refraction, customized to the individual patient.
AN OPTICAL PARAMETRIC OSCILLATOR (OPO) CAN PROVIDE HIGH-POWER, INFRARED TUNABLE OVER A BROAD RANGE. THE DEVELOPMENT OF OPO DEVICES HAS BEEN LIMITED BY THE SCARCITY OF HIGH-QUALITY, NON-LINEAR CRYSTALS AND LOW LASER-DAMAGE THRESHOLD. ZNGEP2 SINGLE CRYSTALS HAVE AN EXCEPTIONALLY HIGH FIGURE OF MERIT (D(2)/N(3), WHERE D IS THE NON-LINEAR COEFFICIENT AND N IS THE INDEX OF REFRACTIONS THAT IS APPROXIMA .... ...
The second round of the presidential elections in the Democratic Republic of Congo will take place on the 29 October. On 30 July, neither the President Joseph Kabila (44.8%) nor the Vice-President Jean-Pierre Bemba (20%) obtained an absolute majority. These elections are a small miracle. But the problems of the Congo will not be solved by elections alone.. The hope for peace was especially poignant for the residents of Kilo on that steamy morning. They stood in the shadow of a mass grave on the crest of the hill, barely a hundred yards from the polling station. Three years ago, dozens of people were killed in a single day. The victims, mostly civilians, were stripped naked, placed face down on the ground and killed with spears. There are countless such mass graves, all over the country.. Unsurprisingly, the hopes for peace are shared by millions of the priests compatriots in this vast country, nearly the size of western Europe. This summers first round of elections and the run-off to be held ...
Looking for online definition of ocular refraction in the Medical Dictionary? ocular refraction explanation free. What is ocular refraction? Meaning of ocular refraction medical term. What does ocular refraction mean?
The mean prediction error of the refractive outcome obtained in our study was 1.03 D (SD, 0.69 D) for SRK II group and 1.14 D (SD, 1.19 D) in Pediatric IOL Calculator group. This showed both groups ended more myopic than anticipated. However, there was no statistically significant different in the mean prediction error in both groups. Even though, the SRK II group had a lower prediction error of 0.11 D compared to the Pediatric IOL Calculator, we could not prove that SRK II is better than Pediatric IOL Calculator or vice versa. Our results showed that for the overall group, the prediction error is satisfactory and is comparable with errors demonstrated in adult group [21].. In our study, we further divided and analyzed the prediction error according to age group, axial lengths and keratometry. We divided the groups according to the age at time of surgery to less than 3 years old, and equal or older than 3 years old; axial length of less than 22 mm, and equal or more than 22 mm; and keratometry ...
Purpose : To investigate the axial length and corneal radius of curvature (AL/CR) ratio in high versus low myopes and its relationship with myopia progression. Methods : Baseline AL/CR ratio of the right eyes of 310 high myopes (aged 7 to 16; myopia ≤ -6.00D) from the ZOC-BHVI High Myopia Registry (2012- 2013, Guangzhou, China) and 733 low myopes (aged 6 to 16; myopia -0.50D to -3.50D) from Vision CRC studies (2010-2014, Guangzhou, China) were calculated. Exclusion criteria were ocular disease, surgery or previous treatment for myopia. All participants underwent measurement of axial lengths (AL), corneal radii of curvature (CR) and cycloplegic objective refraction. Low myopes were followed 6 monthly for 12 months. Parental myopia was documented. General linear model was used to test the relationship between AL/CR ratio and spherical equivalent (SE) after adjusting for parental myopia, gender, age, and high versus low myopia. The progression in AL/CR ratio with progression in SE was assessed in ...
A patients risk of myopia onset can be influenced by various things, including parental myopia, female gender, longer axial length, reduced outdoor time, increased near work time and accommodative insufficiency. Since cycloplegia isnt readily available for most medical practitioners outside of eyecare offices, assessment of spherical equivalent (SE) refraction-commonly used in myopia studies-has limited applicability for other care providers. A recent cohort study observed the performance of SE obtained using non-cycloplegic methods as a predictor of myopia, which would be more accessible across the board for patient assessment. Researchers included 1,022 children aged six to 10 years from two elementary schools in Wenzhou, China. The participants were evaluated at baseline and annual follow-up appointments for three years. The doctors performed non-cycloplegic refraction, ocular biometry and accommodation measurements. A total of 830 of the students were non-myopic at baseline. Two years into ...
Looking for online definition of Complex index of refraction in the Medical Dictionary? Complex index of refraction explanation free. What is Complex index of refraction? Meaning of Complex index of refraction medical term. What does Complex index of refraction mean?
PURPOSE. To examine the association between the anthropometric measurements of height, weight, body mass index (BMI) and refraction and other ocular parameters in Singapore Chinese children. METHODS. In a cross-sectional study of 1449 Chinese school-children, aged 7 to 9 years, from three Singapore schools, height and weight were measured according to standard protocol, and BMI was calculated. Refractive error and corneal curvature measures were determined by autorefraction in eyes under cycloplegia. Axial length, vitreous chamber depth, lens thickness, and anterior chamber depth were measured using A-scan biometry ultrasonography. RESULTS. In comparison with the children with height in the first quartile for a given age and gender, the eyeball length in children in the fourth quartile was 0.46 mm longer, the vitreous chamber depth 0.46 mm deeper, the corneal radius of curvature 0.10 mm greater (i.e., flatter), refraction more negative by 0.47 D (-0.76 D versus -0.29 D), and axial ...
We present parsimonious refraction interferometry and tomography where a densely populated refraction data set can be obtained from two reciprocal and several infill shot gathers. The assumptions are that the refraction arrivals are head waves, and a pair of reciprocal shot gathers and several infill shot gathers are recorded over the line of interest. Refraction traveltimes from these shot gathers are picked and spawned into O(N2) virtual refraction traveltimes generated by N virtual sources, where N is the number of geophones in the 2D survey. The virtual traveltimes can be inverted to give the velocity tomogram. This enormous increase in the number of traveltime picks and associated rays, compared to the many fewer traveltimes from the reciprocal and infill shot gathers, allows for increased model resolution and a better condition number with the system of normal equations. A significant benefit is that the parsimonious survey and the associated traveltime picking is far less time consuming ...
Mean spherical equivalent refraction treated was -6.56±2.74D (range: -2.25 to -13.00D). Median age was 33 years (range: 19 to 66 years). After SMILE, central corneal sensation dropped from 54-mm preoperatively to 32-mm (day one), rising to 40-mm (1 week), 44-mm (1 month), 49-mm (3 months), 54-mm (6 months), and 55-mm (12 months). Corneal sensation had reached baseline by 1, 3, 6, and 12 months in 62%, 76%, 89%, and 90% of eyes respectively. Twenty LASIK studies were identified; central corneal sensation dropped from 56-mm preoperatively to 9-mm (day one), rising to 15-mm (1 week), 22-mm (1 month), 33-mm (3 months), 44-mm (6 months), and 50-mm (12 months). Across the LASIK studies, mean spherical equivalent refraction treated was -4.30D and mean age was 34.2 years ...
PURPOSE: Proper refractive eye growth depends on several features of the visual image and requisite retinal pathways. In this study, we determined the contribution of rod pathways to normal refractive development and form deprivation (FD) myopia by testing Gnat1-/- mice, which lack functional rods due to a mutation in rod transducin-α. METHODS: Refractive development was measured in Gnat1-/- (n = 30-36) and wild-type (WT) mice (n = 5-9) from 4 to 12 weeks of age. FD was induced monocularly from 4 weeks of age using head-mounted diffuser goggles (Gnat1-/-, n = 9-10; WT, n = 7-8). Refractive state and ocular biometry were obtained weekly using a photorefractor, 1310 nm optical coherence tomography, and partial coherence interferometry. We measured retinal dopamine and its metabolite, DOPAC, using HPLC. RESULTS: During normal development, the refractions of WT mice started at 5.36 ± 0.68 diopters (D) and became more hyperopic before plateauing at 7.78 ± 0.64 D. In contrast, refractions in ...
Advanced computerized optical diagnostic equipment is revolutionizing eye care in the 21st century. Refraction is no exception. Traditionally, the refraction of the eye was given with spherical and cylindrical lens powers assumed to be valid across the entire pupil. However, using wavefront sensing, adaptive optics, and new treatment technologies, higher-order aberrations can be measured across the pupil and then modified or eliminated. Research has clearly shown that there are many applications involving these aberrations with diagnosis, treatment, and management of disorders, such as myopia, corneal disorders, presbyopia, cataract, and intraocular lens application and the dynamic changes in refractive state and retinal image quality produced by tear film thinning and accommodation. There are also many related questions that need to be answered regarding the natural stimulus for focusing, the patients perception of the aberrations and their correction, and vision simulation with computational ...
The spherical equivalent before surgery was −4.52 ± 1.96 diopters, falling to −0.22 ± 0.48 diopters after the procedure. Mean uncorrected distance visual acuity post-surgery (UDCVA) was −0.03 ± 0.11 LogMAR. 90.4% achieved UDCVA of at least 0.1 LogMAR (0.8 decimal). 88% showed no refraction one month after surgery and 96.5% had postoperative refraction of ≤0.50 D. Mean asphericity was −0.26 ± 0.19 before surgery and 0.19 ± 0.29 after surgery. Statistically significant differences were found for steep K, flat K, mean K, asphericity, spherical aberration and vertical coma (p < 0.005). On the other hand, no significant differences were found in the Root Mean Square (RMS) for higher order aberrations, horizontal coma or trefoil. Postoperative asphericity correlated strongly with 4th order spherical aberration and vertical coma. Six eyes developed intraoperative complications (confusion between the anterior and posterior planes with stromal damage, loss of suction during the creation of ...
The AOAs stance on these companies prompts the question: Does online refraction actually threaten optometrys model? Consider the lesson of Google Maps.11 Google managed to topple the navigation device market (remember your Tom Tom GPS?) on four main selling points: price, quality, convenience and personalization. Improving on all four of these aspects disrupted the personal navigation device market forever.10 It may be worth discussing with patients whether online refraction companies can beat optometry in any of these selling points. Price. No optometrist would provide a refraction separate from a comprehensive eye exam, explains John Rumpakis, OD, CEO of Practice Resource Management, Inc. However, since thats what these companies are doing, a hypothetical price-by-price comparison may be an appropriate point to discuss with patients. Opternative offers a glasses or contacts prescription for $40 ($60 for both). Although optometry offers a comprehensive exam at an average Medicare ...
This excellent Manual of Refraction has 45 pages and includes the following sections: basic optics visual acuity pinhole refractive errors accommodation presbyopia neutralisation focimetry transposition spherical best sphere equivalent crossed cylinder retinoscopy cycloplegia refraction optical lense basic spectacle dispensing. Price : £5/US$9 + post and packing Post and Packing: Please add £5/$9 (surface) or £9/$16…
PURPOSE: To investigate the association between ocular dominance and refraction. METHODS: A retrospective study of the cycloplegic refraction of 2453 consecutive patients with a mean age of 46 +/- 12 years (range: 18 to 79 years) was performed. One t
A dioptre (uk), or diopter (us), is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres). It is thus a unit of reciprocal length. For example, a 3-dioptre lens brings parallel rays of light to focus at ​1⁄3 metre. A flat window has an optical power of zero dioptres, and does not converge or diverge light. Dioptres are also sometimes used for other reciprocals of distance, particularly radii of curvature and the vergence of optical beams. The usage was proposed by French ophthalmologist Ferdinand Monoyer in 1872, based on earlier use of the term dioptrice by Johannes Kepler. The main benefit of using optical power rather than focal length is that the lensmakers equation has the object distance, image distance, and focal length all as reciprocals. A further benefit is that when relatively thin lenses are placed close together their powers approximately add. Thus, a thin 2-dioptre lens ...
Ray-tracing data are usually given as angles of arrival and departure, transmitter and receiver coordinates, ray length and delay, received power level, and polarity. Usually, these values are given in raw data with some resolution that covers the area of interest where the simulation is performed. There are two main drawbacks of such approach: first, a huge amount of storage capacity is typically needed and second, although the area of interest is covered by a certain resolution, it is nearly impossible to interpolate between sample points and new time, and memory consuming simulations are necessary in order to increase the resolution of the simulations. This paper addresses the two mentioned drawbacks of ray tracing, suggesting a procedure based on the concept of ray entities both to enable continuous interpolation of ray-tracing data and reduce the memory needed for storing data. Ray entity is a set of rays that all undergo the same series of propagation phenomena (direct ray, diffraction, ...
The prevalence rate of myopia is rising rapidly in several Asian countries. A prevalence survey conducted in 1995 of 11178 school children in Taiwan were 12 percent for six year old and 84 percent for teenagers 16 o 18 years. Among them, twenty percent were high myopes. While in the United States and Europe the prevalence rate in older adults is 20% to 50%. The rate of progression of myopia is highest in young children, and the average age of stabilization of myopia is approximately 16 years.The onset of myopia may occur at a relatively young age, leading to higher risks of high myopia (myopia at least 6.0 diopters ) in adulthood. High myopia is associated with potentially blinding complications. Therefore, prevention of myopia progression is important in Taiwan, especially in young children.. There is some evidence that atropine eyedrops retard myopia progression in three randomized clinical trials. It is believed that atropine act on muscarinic receptor located in the sclera and through some ...
Topography & Autorefraction are done at the same time. Topography is a topographical map of your cornea. You may have this done if you have corneal trouble such as Keratoconus or if you have cataracts. Autorefraction provides an objective measurement of your refractive error (the strength glasses you wear). It is particularly important to know your refraction prior and after cataract surgery to calculate the most suitable artificial lens. Currently Medicare does not offer a refund for this vital test.. ...
Case report: A 63 year old female patient consult our clinic for a cataract surgery with IOL implantation. In 1993 she underwent a PRK for her myopia. Her original refraction was 8.0/-0.75/40° at the right eye and -6.75/-0.5/10° at the left eye. As PRK was performed at an other clinic and it was not possible to get any information about keratometry, corneal topography or axial lengt of her eyes before PRK. At her first visit at our eyeclinic her refraction was -3.0/-0.75/18°=20/40 right and -2.75/-0.5/96°=30/50 left. Target refraction after cataract surgery was -2.5 right and -2.5 left. Preoperativly a biometry by IOL-Master® and a corneal topography by C-Scan® were performed. IOL calculation was done with the Oculix-program®. On the first postoperativ day the patient reached a visual acuity of -2.0=40/50 ...
astigmatism - MedHelps astigmatism Center for Information, Symptoms, Resources, Treatments and Tools for astigmatism. Find astigmatism information, treatments for astigmatism and astigmatism symptoms.
Purpose: To investigate whether myopia is becoming more common across Europe and explore whether increasing education levels, an important environmental risk factor for myopia, might explain any temporal trend. Design: Meta-analysis of population-based, cross-sectional studies from the European Eye Epidemiology (E3 ) Consortium. Participants: The E3 Consortium is a collaborative network of epidemiological studies of common eye diseases in adults across Europe. Refractive data were available for 61 946 participants from 15 population-based studies performed between 1990 and 2013; participants had a range of median ages from 44 to 78 years. Methods: Noncycloplegic refraction, year of birth, and highest educational level achieved were obtained for all participants. Myopia was defined as a mean spherical equivalent 0.75 diopters. A random-effects metaanalysis of age-specific myopia prevalence was performed, with sequential analyses stratified by year of birth and highest level of educational ...
The differences that prevail between the cornea that creates the astigmatism and the refractive cylinder that corrects it optically are prevalent and signiftcant, and can play a role in adverse refractive and qualitative outcomes. Addressing these differences during the planning of the surgery provides a uniform paradigm for all astigmatism procedures. Including corneal in addition to refractive values in the treatment plan reduces the amount of overall astigmatism in the eye and provides advantages in outcomes for any corneal refractive astigmatism surgery ...
Screening of refractory defect is one of major reason for amblyopy. Photorefraction is a new method with some advantages in treatment of this problem. In this study the investigators are going to compare the results of this surgery in children between 1 to 10 years old with cycloautorefraction in children above 3 years old ...
In a nearer order from its object, a first lens group which has a negative refractive power, a brightness diaphragm, and a second lens group which has a positive refractive power, and a moving lens group which moves on an optical axis, conditions such as 2≦DL/fW≦6, and −2≦DVH/fW≦0.37 are satisfied under condition that DL (mm) indicates an air-converged length from an end surface near an image in the first lens group to an end surface nearer to an object in the moving lens group, fW (mm) indicates a focal length in an entire system in a wide angle end, DVH (mm) indicates a distance from the end surface near the object in the moving lens group to a front principal point. By doing this, it is possible to provide an objective optical system which can obtain a high magnification while securing a sufficient distance between the diaphragm which is disposed behind the optical axis direction converting element such as a prism to the moving lens group.
The invention is a method of depositing a rugate filter coating on a substrate, with the coating having an index of refraction that varies with the depth thereof. In detail, the method comprising the steps of: a) placing the substrate in an apparatus capable of depositing the coating by a plasma-enhanced chemical vapor deposition process, the apparatus having the capacity to deposit a coating from a mixture of at least two gases and means to control the mixture of gases as a function of time; b) calculating the required refractive index profile wherein the index of refraction is a function of depth thereof using the filter parameters; c) calculating the required total depth of the coating; d) dividing the total depth of the filter into a series of increments having a specific length; e) calculating the index of refraction for each of the series of increments; f) calculating the specific mixture of the at least two gases required to provide the index of refraction for each of the series of increments and
Fingerprint Dive into the research topics of Numerical simulations of surface wave refraction in the North Sea, part 1: Kinematics. Together they form a unique fingerprint. ...
A modified ray-tracing model is applied to analyze the dependence of external quantum efficiency and far-field radiation pattern of AlGaInN light-emitting
Eye practices are valuable in rectifying an assortment of vision issues. These eye practice methods can redress vision conditions, for example, partial blindness and farsightedness. Eye activities can likewise remedy another vision condition called Astigmatism. Astigmatism is characterized as an eye condition whereby your vision is foggy at any separation. A portion of the reasons for astigmatism incorporates sporadically formed ebb and flow has the cornea or eye focal point. You can read at cloud chasers for other Astigmatism causes incorporate eye damage, and complications related with eye surgery.. High glucose levels and issues related with diabetes are likewise contributing components to this vision condition as to diabetes. Such an issue can prompt the development of an abnormally formed eye focal point. This is related with a condition called Lenticular Astigmatism. The most ideal approach to rectify this issue is to bring glucose levels once more into the ordinary range by and by. ...
This page provides relevant content and local businesses that can help with your search for information on Astigmatism Treatment. You will find informative articles about Astigmatism Treatment, including Astigmatism Symptoms And Treatment. Below you will also find local businesses that may provide the products or services you are looking for. Please scroll down to find the local resources in Aztec, NM that can help answer your questions about Astigmatism Treatment.
This page provides relevant content and local businesses that can help with your search for information on Astigmatism Treatment. You will find informative articles about Astigmatism Treatment, including Astigmatism Symptoms And Treatment. Below you will also find local businesses that may provide the products or services you are looking for. Please scroll down to find the local resources in Billings, MT that can help answer your questions about Astigmatism Treatment.
A total of 800 unrelated subjects of Han Chinese ancestry were enrolled in this study, including 300 unrelated individuals with high myopia and 308 emmetropic controls in Guangzhou of other than Chaoshanese origin, and 96 unrelated subjects with moderate to high myopia and 96 emmetropic controls in Guangzhou but from Chaoshan. Two additional cohorts of European ancestry available through dbGAP included 526 unrelated subjects with myopia and 413 emmetropic controls from the KORA cohort and 562 unrelated subjects with myopia and 922 emmetropic controls from the TwinsUK cohort. The baseline characteristics of the subjects are shown in Table 1. The details of the clinical data from individuals of Han Chinese ancestry (Guangzhou and Chaoshan) were described previously [28]. Briefly, the sex and the age between cases and controls were similar, at 50-65% male and with an average age of 21.6-22.2 years. The refraction between the left and right eyes showed no statistical difference. The refraction in ...
The most important subjects of his inquiries are enumerated by Forbes under the following five heads : 1. The laws of polarization by reflection and refraction, and other quantitative laws of phenomena; 2. The discovery of the polarizing structure induced by heat and pressure; 3. The discovery of crystals with two axes of double refraction, and many of the laws of their phenomena, including the connection of optical structure and crystalline forms; 4. The laws of metallic reflection; 5, Experiments on the absorption of light. In this line of investigation the prime importance belongs to the discovery (1) of the connection between the refractive index and the polarizing angle, (2) of biaxal crystals, and (3) of the production of double refraction by irregular heating. These discoveries were promptly acknowledged by those best qualified to estimate their value. So early as the year 1807 the degree of LL.D. was conferred upon Brewster by Marischal College, Aberdeen; in 1815 he was made a member of ...
Open angle glaucoma, ocular hypertension, low-tension glaucoma, and refraction. Arch Ophthalmol 1982;100(9):1464-7. Blondeau P ... Ocular hypotony after retinal vascular occlusion. Trans Ophthalmol Soc U K 1977;97(4):756-67. Perez RN, Phelps CD, Burton TC. ... The "no treatment" approach to ocular hypertension. Surv Ophthalmol 1980;25(3):175-82. Phelps CD, Armaly MF. Measurement of ...
Disorders of ocular muscles, binocular movement, accommodation and refraction. Hidden categories: *All articles with dead ...
Disorders of ocular muscles, binocular movement, accommodation and refraction. Hidden categories: *Articles needing additional ... They are indicated for use in cycloplegic refraction (to paralyze the ciliary muscle in order to determine the true refractive ... Belladonna alkaloids are used for testing the error of refraction and examination of eye. ...
Disorders of ocular muscles, binocular movement, accommodation and refraction. Hidden categories: *Articles needing additional ...
2007;48:2510-9. Mutti DO, Sholtz RI, Friedman NE, Zadnik K. Peripheral refraction and ocular shape in children. Investigative ... Ocular component data in schoolchildren as a function of age and gender. Optometry and Vision Science: official publication of ... Ocular predictors of the onset of juvenile myopia. Investigative Ophthalmology & Visual Science. 1999;40:1936-43. Jones-Jordan ... Comparison of ocular component growth curves among refractive error groups in children. Investigative Ophthalmology & Visual ...
Index myopia is attributed to variation in the index of refraction of one or more of the ocular media. As with any optical ... Index myopia is attributed to variation in the index of refraction of one or more of the ocular media. Cataracts may lead to ... During a refraction, an autorefractor or retinoscope is used to give an initial objective assessment of the refractive status ... Youth onset myopia occurs in early childhood or teenage, and the ocular power can keep varying until the age of 21, before ...
Index myopia is attributed to variation in the index of refraction of one or more of the ocular media.[50] Cataracts may lead ... Index myopia is attributed to variation in the index of refraction of one or more of the ocular media.[50] ... a b Duke-Elder, Sir Stewart (1969). The Practice of Refraction (8th ed.). St. Louis: The C.V. Mosby Company. ISBN 0-7000-1410-1 ... Young, FA (1962). "The effect of nearwork illumination level on monkey refraction". Am J Optom and Arch Am Acad Optom. 39 (2): ...
... refraction, ocular MeSH G11.697.677.911 - vision MeSH G11.697.677.911.500 - phosphenes MeSH G11.697.677.911.700 - vision, ... ocular MeSH G11.697.716.154 - adaptation, ocular MeSH G11.697.716.154.371 - dark adaptation MeSH G11.697.716.182 - blinking ... MeSH G11.697.716.260 - eye movements MeSH G11.697.716.260.217 - convergence, ocular MeSH G11.697.716.260.253 - fixation, ocular ... ocular MeSH G11.697.677.330 - evoked potentials, visual MeSH G11.697.677.340 - eye color MeSH G11.697.677.360 - figural ...
... refraction, ocular MeSH E01.370.380.850.900 - vision screening MeSH E01.370.382.375 - hearing tests MeSH E01.370.382.375.050 - ... ocular MeSH E01.370.380.850 - vision tests MeSH E01.370.380.850.150 - color perception tests MeSH E01.370.380.850.600 - ...
Eser I, Durrie DS, Schwendeman F, Stahl JE (September 2008). "Association between ocular dominance and refraction". Journal of ... Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other ... Ocular dominance column Right- and left-hand traffic Chaurasia BD, Mathur BB (1976). "Eyedness". Acta Anatomica. 96 (2): 301-5 ... Handa T, Mukuno K, Uozato H, Niida T, Shoji N, Minei R, Nitta M, Shimizu K (April 2004). "Ocular dominance and patient ...
... performed during an eye examination that enables diagnosis Ocular tonometry to determine intraocular pressure Refraction ... Some of them are: Anterior segment surgery Cornea, ocular surface, and external disease Glaucoma Neuro-ophthalmology Ocular ... ocular oncology, Ocular pathology, or neuro-ophthalmology. Approximately 35 vacancies open per year for ophthalmology residency ... Eye surgery, also known as ocular surgery, is surgery performed on the eye or its adnexa by an ophthalmologist. The eye is a ...
... or through appropriate ocular exercises. Refraction "Pseudomyopia - symptoms". PSEUDOMYOPIA - false nearsightedness. "Acute ... Organic causes may include systemic or ocular medications, brain stem injury, or active ocular inflammation such as uveitis. ... The diagnosis is done by cycloplegic refraction using a strong cycloplegic like atropine or homatropine eye drops. ... Functional pseudomyopia is managed though modification of working conditions, an updated refraction, typically involving a ...
Accommodation and Convergence of the Eyes (1882) Tests and Studies of the Ocular Muscles (1898) Golden Rules of Refraction ( ...
Normal ocular health Age 18 years or older Stable refraction error (no noticeable change in the last year) correctable to 20/40 ... Collagen vascular disease (e.g., corneal ulceration or melting) Ocular disease (e.g., dry eye, keratoconus, glaucoma) Systemic ... Brush PRK to denude the epithelium, instead of alcohol based techniques, also result in quantitatively lower ocular dryness ... or starburst aberrations Increased ocular straylight Under- or overcorrection Recurrence of myopia Corneal haze Scarring ...
Eye floaters - ocular mechanical stress created by LASIK have the potential to damage the vitreous, retina, and macula causing ... The purely refraction-based approach represented by wavefront analysis actually conflicts with corneal surgical experience ... Ocular neuropathic pain (corneal neuralgia); rare Depression and suicide In October 2009, the FDA, the National Eye Institute ( ... Wavefront is showing signs of success, but can it do it alone? Ocular Surgery News. September 1, 2000, page 41. EW Dialogue: ...
They work closely with Optometrists in refractive therapy and refraction. There are a lot of ocular conditions in Ghana and as ... The services that eye care professionals offer are varied and include: Cataracts surgery Glaucoma surgery Refraction ... Retinopathy Glaucoma Bacterial Infections Viral Infections Agricultural injuries to the eye Trauma HIV/AIDS associated ocular ...
These play a role in creating a smooth surface to facilitate refraction, lubricating the movement of the eyelid, passively ... 44(2): p. 581-9. Akpek, E.K. and J.D. Gottsch, Immune defense at the ocular surface. Eye, 2003. 17(8): p. 949-56. Hein, W.R., ... The ocular immune system protects the eye from infection and regulates healing processes following injuries. The interior of ... However, the role of MALT in human ocular defenses is not fully understood. However, it is known that the lacrimal glands and ...
1] Presumed Ocular Histoplasmosis Syndrome *^ Stefan Dithmar; Frank Gerhard Holz (28 April 2008). Fluorescence Angiography in ... Presumed ocular histoplasmosis syndrome (POHS) is a syndrome affecting the eye, which is characterized by peripheral atrophic ... Thuruthumaly C; Yee D. C.; Rao P. K. (2014). "Presumed ocular histoplasmosis". Current Opinion in Ophthalmology. 25 (6): 508-12 ... Presumed ocular histoplasmosis syndrome and age-related macular degeneration (AMD) have been successfully treated with laser, ...
Textbook of Ophthalmology (1954) A Century of International Ophthalmology (1958) Neuro-ophthalmology (1971) Ocular Motility and ... Strabismus (1973) System of Ophthalmology (multiple editions) Practice of refraction (multiple editions) Lyle, T. K.; Miller, S ...
A measure called CorT total includes this posterior corneal data and more accurately reflects refraction compared with regular ... Pavan-Langston, Deborah (2007). Manual of Ocular Diagnosis and Therapy. Hagerstown, MD: Lippincott Williams & Wilkins. p. 405. ... Biro, A (25 November 2012). "New measurement method quantifies corneal astigmatism". Ocular Surgery News. US edition. Retrieved ...
925-939...................................Refraction and errors of refraction and accommodation 939.2-981 ... Ocular therapeutics 110-320...................................Otology. Diseases of the ear 341-437 ...
... juvenile and presenile cataract 366.1 Senile cataract 366.2 Traumatic cataract 366.3 Cataract secondary to ocular disorders ... associated with other disorders 366.5 After-cataract 366.8 Other cataract 366.9 Unspecified 367 Disorders of refraction and ... and with systemic syndromes 365.5 Glaucoma associated with disorders of the lens 365.6 Glaucoma associated with other ocular ...
Disorders of ocular muscles, binocular movement, accommodation and refraction. *Abducens nerve. Hidden categories: *All ... "Cranial Nerve VI Palsy", Handbook of Ocular Disease Management, 2000 - 2001 Jobson Publishing L.L.C. (2000-2001).[2] ... The unilateral abducens nerve palsy is the most common of the isolated ocular motor nerve palsies.[3] ... Thus, the toxin works both therapeutically, by helping to reduce symptoms and enhancing the prospects for fuller ocular ...
A refraction procedure consists of two parts: objective and subjective. An objective refraction is a refraction obtained ... Ocular motility should always be tested, especially when patients complain of double vision or physicians suspect neurologic ... especially when trying to obtain an accurate refraction in young children who may skew refraction measurements by adjusting ... A subjective refraction requires responses from the patient. Typically, the patient will sit behind a phoropter or wear a trial ...
Ocular motor control neurons Neurons that are interposed between the afferent and efferent limbs of this circuit and include ... Theory and practice of optics and refraction (2nd ed.). Elsevier. pp. 98-99. ISBN 978-81-312-1132-8. Accommodation at Georgia ... "Chapter 7: Ocular Motor System". Neuroscience Online: An Electronic Textbook for the Neurosciences. Department of Neurobiology ... Three regions make up the accommodation neural circuit, the afferent limb, the efferent limb and the ocular motor neurons that ...
Unlike the red reflex, this can help determine if the patient has normal ocular alignment. In order to perform this test the ... The inequality of red reflection in both the eyes indicates unequal refraction, indicating a refractive error. Pupil of a ... Regardless of the effectiveness, it is a fast, inexpensive, and noninvasive exam that could identify ocular pathology which ... The objective is to detect ocular pathology that needs early intervention and ophthalmology referral to prevent visual ...
"Errors of refraction and binocular optical defects". Theory and Practice of Optics and Refraction (2 ed.). p. 77. Wajuihian SO ... "Iris and Ciliary body". Current Ocular Therapy (6 ed.). p. 518.CS1 maint: multiple names: authors list (link) Mitchel Scheiman ... Optical: Cycloplegic refraction, and correction of Refractive errors if any Vision therapy General: Relax from near work Spasm ... "anomalies of accommodation and convergence". Theory and Practice of Optics and Refraction (2 ed.). Elsevier. pp. 105-106. ...
Book on eye diseases, therapeutics and ocular surgery. Ein neues Ophthalmotrop, 1857 - A new ophthalmotrope. Das Stereoscop : ... On the anomalies of accommodation and refraction of the Eye by Franciscus Cornelis Donders and William Daniel Moore Bernard ...
... shining in the night sky-except that ocular asteroids are often quite mobile. Ocular asteroids must be distinguished from the ... Wong S, Sampath R (2002). "Erroneous automated refraction in a case of asteroid hyalois". J Cataract Refract Surg. 28 (9): 1707 ... ISBN 0-683-30076-8. Bjerk, Ellen (2004). "Ocular Disease of the Aging Dog". Proceedings of the 29th World Congress of the World ...
List of systemic diseases with ocular manifestations. References[edit]. *^ a b c Matejcek, A; Goldman, RD (November 2013). " ...
... is a category of vision loss or visual impairment that is caused by factors unrelated to refractive errors or coexisting ocular ... training to rule out potential medical or surgical correction for the problem and to establish a careful baseline refraction ... inflammatory ocular hypertension syndrome (IOHS); 2) severe uveitic angle closure; 3) corticosteroid-induced; and 4) a ... uveitis refers to a complex category of ocular diseases that can cause blindness if either left untreated or improperly ...
Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Retinopathy *diabetic ...
Patient remains asymptomatic until epithelial erosions precipitate acute episodes of ocular hyperemia, pain, and photophobia. ...
Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Branch retinal artery occlusion ...
Hodge C, Lawless M (July 2008). "Ocular emergencies". Aust Fam Physician. 37 (7): 506-9. PMID 18592066.. ... Jimmy D. Bartlett; Siret D. Jaanus (2008). Clinical Ocular Pharmacology. Elsevier Health Sciences. pp. 454-. ISBN 978-0-7506- ... they are rarely done because of the cost and the general dearth of laboratory staff experienced in handling ocular specimens. ... "The ocular application of povidone-iodine". Community Eye Health / International Centre for Eye Health. 16 (46): 30-1. PMC ...
Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Branch retinal artery occlusion ...
Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Branch retinal artery occlusion ...
Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Branch retinal artery occlusion ...
Refraction[edit]. This section contains information of unclear or questionable importance or relevance to the article's subject ... and obviously the lack of an experimental investigation of ocular tracts. ... refraction, and reflection.[57] His analyses of reflection and refraction considered the vertical and horizontal components of ... 2010), Alhacen on Refraction: a critical edition, with English translation and commentary, of Book 7 of Alhacen's De aspectibus ...
... especially when used to treat ocular tumors. ... Refraction. *Refractive error *Hyperopia. *Myopia. *Astigmatism ...
Eye care/screening for children within primary health care is important as catching ocular disease issues can lead to better ...
... previous ocular penetrating trauma or surgery, and other concomitant ocular disease similar to VKH disease.[2][6][11] ... glaucoma and ocular hypertension.[2][3][5][6] Full-blown recurrences are, however, rare after the acute stage is over.[8] ... ocular complications may require an subtenon[6] or intravitreous injection of corticosteroids[4][6] or bevacizumab.[9] In ... Ocular MRI may be helpful[6] and auditory symptoms should undergo audiologic testing.[6] Histopathology findings from eye and ...
Fraunfelder, Frederick T.; Fraunfelder, Frederick W.; Chambers, Wiley A. (2014). Drug-Induced Ocular Side Effects: Clinical ... Ocular Toxicology E-Book. Elsevier Health Sciences. p. 79. ISBN 978-0-323-31985-0. .. ...
List of systemic diseases with ocular manifestations. References[edit]. *^ Ketring, Kerry I. (2006). "Emergency Treatment for ... This type causes fewer problems than anterior lens luxation, although glaucoma or ocular inflammation may occur. Surgery is ... leading to an obstruction of outflow of aqueous humour and subsequent increase in ocular pressure (glaucoma).[1] Better ...
Berson, E. L.; Rosner, B; Sandberg, M. A.; Weigel-Difranco, C; Dryja, T. P. (1991). "Ocular findings in patients with autosomal ... Berson, Eliot L.; Rosner, B; Sandberg, M. A.; Dryja, T. P. (1991). "Ocular Findings in Patients with Autosomal Dominant ...
Thibos, L. N.; Bradley, A; Still, D. L.; Zhang, X; Howarth, P. A. (1990). "Theory and measurement of ocular chromatic ... Newton's theories about white light being composed of a spectrum of colors led him to the conclusion that uneven refraction of ... Kruger, P. B.; Mathews, S; Aggarwala, K. R.; Sanchez, N (1993). "Chromatic aberration and ocular focus: Fincham revisited". ... "Spectral bandwidth and ocular accommodation". Journal of the Optical Society of America A. 12 (3): 450-5. Bibcode:1995JOSAA.. ...
Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Retinopathy *diabetic ...
Ocular straylight. References[edit]. *^ a b Cline D; Hofstetter HW; Griffin JR. Dictionary of Visual Science. 4th ed. ... Floaters are visible because of the shadows they cast on the retina[4] or refraction of the light that passes through them, and ... They also carry a high risk of damage to surrounding ocular tissue. Accordingly, vitreolysis is not widely practised, being ...
... similar to that seen in ocular ischemic syndrome. Since the central retinal artery and vein are the sole source of blood supply ...
Dickerman, RD; Smith, GH; Langham-Roof, L; McConathy, WJ; East, JW; Smith, AB (April 1999). "Intra-ocular pressure changes ... cycloplegic refraction, fundus examination and threshold visual field every 4 to 6 weeks × 6 months, repeat MRI in 6 months ≥ ... cycloplegic refraction, fundus examination and threshold visual field every 4 to 6 weeks × 6 months, repeat MRI in 6 months ≥ ... "Non-invasive assessment of intracranial pressure using ocular sonography in neurocritical care patients". Intensive Care Med. ...
In particular, acrylic-type contact lenses are useful for cataract surgery in patients that have recurrent ocular inflammation ... Swart created tools to work the Lucite for sculpture and mixed chemicals to bring about certain effects of color and refraction ...
... ocular anatomy, ocular disease, pharmacology, ocular pharmacology, neuroanatomy and neurophysiology of the visual system, ... These professionals specialized in optics and refraction. In 1933, under Decrees 449 and 1291, the Colombian Government ... ocular photography or ocular neurology; 2) BCs in ophthalmic technology, requiring four 4 years of training; and BCs in optical ... They can also remove ocular foreign bodies and can order blood panels or imaging studies (CT/MRI). However, optometrists are ...
This typically includes a refraction to determine the proper power of the lens and an assessment of the health of the eye's ... Like any contact lens, cosmetic lenses carry risks of mild to serious complications, including ocular redness, irritation and ... However, like da Vinci's, Young's device was not intended to correct refraction errors. Sir John Herschel, in a footnote of the ... as they sat only on the cornea rather than across all of the visible ocular surface, and could be worn up to sixteen hours a ...
METHODS: A retrospective study of the cycloplegic refraction of 2453 consecutive patients with a mean age of 46 +/- 12 years ( ... To investigate the association between ocular dominance and refraction. ... Dominance, Ocular / physiology*. Female. Humans. Male. Middle Aged. Refraction, Ocular / physiology*. Retrospective Studies. ... PURPOSE: To investigate the association between ocular dominance and refraction. METHODS: A retrospective study of the ...
... on ocular refraction. (B) Effect of SL (430 nm, ▴), BL (○), and transfer from SL to BL at week 10 (SLR ▪) on ocular refraction ... on ocular refraction. (B) Effect of SL (430 nm, ▴), BL (○), and transfer from SL to BL at week 10 (SLR ▪) on ocular refraction ... on ocular refraction. (B) Effect of SL (430 nm, ▴), BL (○), and transfer from SL to BL at week 10 (SLR ▪) on ocular refraction ... on ocular refraction. (B) Effect of SL (430 nm, ▴), BL (○), and transfer from SL to BL at week 10 (SLR ▪) on ocular refraction ...
... ocular refraction explanation free. What is ocular refraction? Meaning of ocular refraction medical term. What does ocular ... Looking for online definition of ocular refraction in the Medical Dictionary? ... ocular refraction. See: vision pathway. ocular refraction. Refraction of eye.. static refraction. Refraction of the eye when ... dynamic refraction refraction of the eye during accommodation.. ocular refraction the refraction of light produced by the media ...
... dc.contributor.advisor. Stell, ... McGuire, J. J. (1999). Visual induction of fos in amacrine cells regulates ocular growth and refraction in chick (Unpublished ... Visual induction of fos in amacrine cells regulates ocular growth and refraction in chick. ...
Association Between Ocular Dominance and Refraction Ilker Eser, MD; Frank Schwendeman, OD; Daniel S Durrie, MD; Jason E Stahl, ... Influence of Age on Ocular Wavefront Aberration Changes With Accommodation Yoshihiko Iida, MD; Misae Ito, CO; Kimiya Shimizu, ...
Pre-term delivery and subsequent ocular development. 3. Refraction. Myopia of prematurity. Acta Ophthalmol Scand.1996;74 :297- ... The control children received the same tests, except for cycloplegic refraction and ocular ultrasound, which would have caused ... Ocular Components (mean [SD]): Comparison Between Follow-Up Study Cohort and Published Normative Data13 and by Stage of ROP ... Controlled study of ocular morbidity in school children born preterm. Br J Ophthalmol.1992;76 :520- 524. ...
Refraction, Ocular.. Subject:. Lenses. Subject:. Physiological optics. Subject:. Health and Medicine-Medical Specialties. ... 9. Refraction by the Eye.. 10. Optics of Ametropia.. 11. Presbyopia.. 12. Contact Lenses.. 13. Optics of Low Vision Aids.. 14. ... 3. Refraction of Light.. 4. Prisms.. 5. Spherical Lenses.. 6. Astigmatic Lenses.. 7. Optical Prescriptions, Spectacle Lenses. ...
... clinical refraction; cornea and external eye; glaucoma; neuro-ophthalmology; ocular inflammation; ocular motility; ...
Short-Term Changes in Ocular Biometry and Refraction After Discontinuation of Long-Term Orthokeratology. Santodomingo-Rubido, ... Short-Term Changes in Ocular Biometry and Refraction After Discontinuation of Long-Term Orthokeratology. Santodomingo-Rubido, ... Short-Term Changes in Ocular Biometry and Refraction After Discontinuation of Long-Term Orthokeratology. Santodomingo-Rubido, ... Short-Term Changes in Ocular Biometry and Refraction After Discontinuation of Long-Term Orthokeratology. Santodomingo-Rubido, ...
Association between stature, ocular biometry and refraction in an adult population in rural Myanmar: the Meiktila eye study. ... Associations between anthropometric indicators and both refraction and ocular biometrics in a cross-sectional study of Chinese ... The relationship between ocular dimensions and refraction with adult stature: the Tanjong Pagar Survey. Invest Ophthalmol Vis ... Refraction. Refractive errors in both eyes were measured in participants whose uncorrected visual acuity (UCVA) in either eye ...
INVOLVEMENT OF MULTIPLE MOLECULAR PATHWAYS IN THE GENETICS OF OCULAR REFRACTION AND MYOPIA. Wojciechowski, Robert; Cheng, Ching ... epidemiological and genome-wide association studies into the molecular pathways and genetics underlying ocular refraction and ...
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The ocular biometric measurements and prediction of postoperative refraction using Galilei G6(R) were as accurate as with IOL ... Comparison of Ocular Biometry and Postoperative Refraction in Cataract Patients between Galilei-G6(R) and IOL Master(R) ... Comparison of Ocular Biometry and Postoperative Refraction in Cataract Patients between Ga ... and the predictive error which subtracts predictive refraction from postoperative refraction was compared between the ocular ...
French, AN, ODonoghue, L, Morgan, IG, Saunders, KJ, Mitchell, P and Rose, KA (2012) Comparison of Refraction and Ocular ... Purpose: To compare refraction and ocular biometry in European Caucasian children aged 6-7 years and 12-13 years living in ... Comparison of Refraction and Ocular Biometry in European Caucasian Children Living in Northern Ireland and Sydney, Australia ... and ocular biometry (IOLMaster, Carl Ziess). Hyperopia was defined as a right spherical equivalent refraction (SER) of ≥+2.00 ...
Refraction, Ocular * Wound Healing ...
Refraction, Ocular* * Species Specificity ...
Refraction, Ocular: see Eye -- Accommodation and refraction. *Refraction of the eye: see Eye -- Accommodation and refraction ... Refraction -- Early works to 1800 (1 title, plus subtopics). * ...
... ocular refraction (automatic refraction), spectacle refraction, axial length (optical, ultrasound), anterior segment biometry ( ... ocular refraction (automatic refraction), spectacle refraction, axial length (optical, ultrasound), anterior segment biometry ( ... The purpose of this study is to determine the average values of human ocular biometry and to correlate these values with visual ... to obtain a predetermined number of valid ocular biometry measurements per participating site [ Time Frame: 19 months ]. The ...
Disorders of ocular muscles, binocular movement, accommodation and refraction. Hidden categories: *All articles with dead ...
Disorders of ocular muscles, binocular movement, accommodation and refraction. Hidden categories: *Articles needing additional ... They are indicated for use in cycloplegic refraction (to paralyze the ciliary muscle in order to determine the true refractive ... Belladonna alkaloids are used for testing the error of refraction and examination of eye. ...
Ocular movement testing. *Measures eye movement in response to images, light and other triggers. ... Refraction. *Measures a persons prescription for eyeglasses or contact lenses.. Patient Needing Contact Lenses:. If you prefer ...
Eser I, Durrie DS, Schwendeman F, Stahl JE (September 2008). "Association between ocular dominance and refraction". Journal of ... Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other ... Ocular dominance column Right- and left-hand traffic Chaurasia BD, Mathur BB (1976). "Eyedness". Acta Anatomica. 96 (2): 301-5 ... Handa T, Mukuno K, Uozato H, Niida T, Shoji N, Minei R, Nitta M, Shimizu K (April 2004). "Ocular dominance and patient ...
Refraction, Ocular. *Refractive Errors/epidemiology. *Refractive Errors/therapy*. *Vision Screening/organization & ... Social, demographic, and ocular parameters were similar in the 2 groups. Average SE refractive error was -2.57+/-1.31 (mean ... Refractive error was determined by cycloplegic subjective refraction. Students were randomly assigned to receive RMS or custom ... 1 D hyperopic anisometropia and ocular disease affecting vision. ...
medical and ocular history. *visual acuity testing. *refraction to measure the glasses or lens correction ... oral ocular hypotensive or pressure-lowering medications: most commonly acetazolamide (Diamox) or methazolamide (MZM). ... It requires a cobalt blue light source and a small droplet of fluorescein on the ocular surface. A tiny pressure sensor ... These tests together give a complete picture of the patients ocular health and therefore the risks for developing or ...
vision tests/ or refraction, ocular/ or vision screening/. *. limit 1 to ("newborn infant (birth to 1 month)" or "infant (1-23 ... The VIP study found that addition of an ocular alignment test (cover-uncover test, the Stereo Smile II, or the MTI ... Preschool vision screening typically includes measurement of visual acuity (Table 3), ocular alignment, and stereoacuity.86 ... For screening tests, we included tests of visual acuity, ocular alignment, and stereoacuity; photoscreeners; and autorefractors ...
Ocular and Systemic Side Effects of Drugs Conference scheduled on July 19-20, 2022 in July 2022 in Paris is for the researchers ... Antibiotics in ocular infections. Uveitis, intraocular inflammation. Recent developments in immunotherapy. Ocular refraction ... Ocular and Systemic Side Effects of Drugs. ICOSSED 2022: 16. International Conference on Ocular and Systemic Side Effects of ... Impaired ocular blood flow regulation in open angle glaucoma Endothelin in glaucoma treatment. Complications and management of ...
Antibiotics in ocular infections. Uveitis, intraocular inflammation. Recent developments in immunotherapy. Ocular refraction ... Impaired ocular blood flow regulation in open angle glaucoma Endothelin in glaucoma treatment. Complications and management of ... Ocular and systemic side effects of drugs. IVT injection-sparing approaches. Extended activity approaches. Sustained delivery ... Impact of possitron emission tomography in ocular adnexae lymphoma. Updates in management of thyroid eye disease. Genetic eye ...
Optics & Refraction, Paul Riordan-Eva. 22. Ophthalmic Therapeutics, Allan J. Flach and Frederick W. Fraunfelder. 23. Lasers in ... Ocular Disorders Associated with Systemic Diseases, Edward Pringle and Elizabeth M. Graham. 16. Immunologic Diseases of the Eye ... Chapter 15.Ocular Disorders Associated with Systemic Diseases; Chapter 16.Immunologic Diseases of the Eye; Chapter 17.Special ... Subjects of Pediatric Interest; Chapter 18.Genetic Aspects; Chapter 19.Trauma; Chapter 20.Optics & Refraction; Chapter 21. ...
Keywords : Biometry; Intraocular lens implantation; Ocular refraction; Methods; Postoperative period; Phacoemulsification; ... Results: Comparing the final refraction planned by the surgeon, based on biometry with the SRK/T formula, and the postoperative ...
In the premature subgroup, we also examined the correlation between BW and GA with the four ocular parameters of refraction, ... Fundus appearance and ocular functions in cicatricial phase of very low birth weight infants. Jpn J Ophthalmol 1977;21:421-35. ... The refraction of the premature group could have been influenced by the ROP since the neural retina is a controller of eye ... Kent D , Pennie F, Laws D, et al. The influence of retinopathy of prematurity on ocular growth. Eye 2000;14:23-9. ...
  • METHODS: A retrospective study of the cycloplegic refraction of 2453 consecutive patients with a mean age of 46 +/- 12 years (range: 18 to 79 years) was performed. (biomedsearch.com)
  • cycloplegic refraction a type of static refraction , measured after lens accommodation is paralyzed by administration of cycloplegic eye drops. (thefreedictionary.com)
  • They are indicated for use in cycloplegic refraction (to paralyze the ciliary muscle in order to determine the true refractive error of the eye) and the treatment of uveitis . (wikipedia.org)
  • Refractive error was determined by cycloplegic subjective refraction. (nih.gov)
  • Statistically significant between groups differences were found for cycloplegic refraction (p = 0.02 for both eyes) and keratometry (p = 0.001 for both eyes). (bmj.com)
  • Cycloplegic Refraction - Refraction is the procedure by which the natural optical error is characterized and quantified. (nasa.gov)
  • Cycloplegic refraction refers to refraction done with a cycloplegic agent to dilate the pupil. (nasa.gov)
  • Ideally, a child with myopia should undergo cycloplegic refraction at the initial presentation and then at least every 12 months. (cehjournal.org)
  • However, if cycloplegic refraction is not possible, a careful subjective refraction must suffice. (cehjournal.org)
  • 1,2 Therefore, tropicamide 1% is worth considering for cycloplegic refraction as it reduces the duration of glare and near symptoms compared to other options. (cehjournal.org)
  • If conducting cycloplegic refraction, inform patients that the eye drops may sting for a few seconds before instilling them into the eye. (cehjournal.org)
  • Use the cycloplegic refraction results from retinoscopy or autorefraction as the starting point and then refine to achieve the best possible VA. If there is a large difference between the cycloplegia objective and subjective refraction, recheck your results. (cehjournal.org)
  • in addition, the anterior ocular segment and the fundus were examined, as was the apparent and cycloplegic refraction. (mendeley.com)
  • Association between ocular dominance and refraction. (biomedsearch.com)
  • PURPOSE: To investigate the association between ocular dominance and refraction. (biomedsearch.com)
  • Any disruptive factor that prevents the eyes from seeing equally, fusing their images, or working together (coordination), whether it be an imbalance of refractive errors between the eyes (anisometropia), a lens opacity obstructing normal vision (cataract), or an ocular misalignment (strabismus), can potentially cause loss of vision (amblyopia). (healio.com)
  • Exclusion criteria were orbital trauma history, any ocular pathology, previous eye surgery, strabismus and topical medication use. (escrs.org)
  • Other ocular problems included vernal keratoconjunctivitis, vitamin A deficiency, microbial conjunctivitis, strabismus and corneal opacity. (who.int)
  • Down syndrome (DS) is the most common human chromosomal anomaly, and is reportedly associated with incidences of refractive error, amblyopia, strabismus, nystagmus, cataract, and other ocular disorders. (dovepress.com)
  • 4,5 ) Timely diagnosis and appropriate treatment of children with strabismus and/or amblyopia is likely to reduce the prevalence of persistent amblyopia and ocular misalignment in adults. (mrcophth.com)
  • The axial length, anterior chamber depth, and keratometry were measured using 2 types of partial coherence interferometries (Galilei G6(R) and IOL Master(R)). The SRK/T formula was used to calculate IOL power and the predictive error which subtracts predictive refraction from postoperative refraction was compared between the ocular biometry devices . (bvsalud.org)
  • Purpose: To compare refraction and ocular biometry in European Caucasian children aged 6-7 years and 12-13 years living in Sydney, Australia and Northern Ireland. (ulster.ac.uk)
  • Shin-Nippon SRW-5000) and ocular biometry (IOLMaster, Carl Ziess). (ulster.ac.uk)
  • The purpose of this study is to determine the average values of human ocular biometry and to correlate these values with visual function. (clinicaltrials.gov)
  • Refractive state and ocular biometry were obtained weekly using a photorefractor, 1310 nm optical coherence tomography, and partial coherence interferometry. (arvojournals.org)
  • Additionally, longitudinal measurement of ocular biometry revealed a significant increase in crystalline lens thickness and a corresponding decrease in anterior chamber depth after 2.5 years (n=51). (bl.uk)
  • The change in ocular biometry per dioptre of accommodation exerted remained invariant after 2.5 years. (bl.uk)
  • Hyperopia was defined as a right spherical equivalent refraction (SER) of ≥+2.00 dioptres (D), myopia as ≤-0.50D and astigmatism as a cylindrical error of ≥1.00D.Results: The mean SER was similar at age 6-7 yrs (p=0.9), however, at 12-13 yrs, children in Northern Ireland had a significantly less hyperopic mean SER (+0.66D) than children in Sydney (+0.83D, p=0.008). (ulster.ac.uk)
  • Refraction is essentially the same as the retinoscopy other than it tests your eyes using an instrument called a phoropter for hyperopia (farsightedness), myopia (nearsightedness), astigmatism and presbyopia. (articlecube.com)
  • 1 - 6 Peripheral refraction was first implicated as a risk factor for the onset of myopia by Hoogerheide et al. (arvojournals.org)
  • Experimental designs that concurrently compare myopia and hyperopia induction enable identification of genes with expression profiles that are discriminatory for different ocular growth trajectories. (frontiersin.org)
  • An accurate refraction is very important in diagnosing myopia and monitoring myopia progression. (cehjournal.org)
  • CONCLUSIONS: Ocular features of LDS include decreased central corneal thickness and mild myopia. (medworm.com)
  • Human refraction is leptokurtic (Figure 1) and negatively skewed (toward myopia). (aao.org)
  • Induced negative lens defocus results in accelerated ocular elongation and myopia. (arvojournals.org)
  • Belladonna alkaloids are used for testing the error of refraction and examination of eye. (wikipedia.org)
  • Clinical Procedures for Ocular Examination, Third Edition", is a must-have resource for students and practitioners involved in eye care. (waterstones.com)
  • All children underwent complete ophthalmologic examination including measurement of Snellen visual acuity as decimals, refraction, and dilated funduscopy. (hindawi.com)
  • Each patient was provided with a complete ophthalmological assessment including best corrected visual acuity, refraction, slit lamp and fundus examination. (issuu.com)
  • Examination showed a shallow anterior chamber, moderate diffuse corneal edema, and ocular hypertension. (medworm.com)
  • Through examination of the subjects' medical charts, we investigated the development and changes of refractive errors and VA, best-corrected VA (BCVA), and systemic and ocular anomalies. (dovepress.com)
  • Many eye conditions, such as corneal ulcer, glaucoma, ocular trauma or eye surgery in a young child may lead to stimulus deprivation and, if suspected, this should be specifically excluded on examination. (mrcophth.com)
  • 153 women) with no corneal disease underwent an exhaustive ocular examination. (ucm.es)
  • OSAS has major consequences on the ocular level since it is associated with a higher frequency of optic neuropathies, such as glaucoma and nonarteritic ischemic optic neuropathy (NAION), both with functional severe prognosis. (clinicaltrials.gov)
  • The children with neurologic sequela such as mental retardation and cerebral palsy and those who had ocular diseases such as glaucoma, cataract, and history of treatment for retinopathy of prematurity and those who had undergone any ocular surgery were excluded. (hindawi.com)
  • The all-new 3rd generation Ocular Response Analyzer, the only tonometer capable of measuring Corneal Hysteresis, a superior predictor of glaucoma progression. (reichert.com)
  • ocular refraction the refraction of light produced by the media of the normal eye and resulting in the focusing of images upon the retina. (thefreedictionary.com)
  • There has also been much study of how the retina affects eye growth and refraction. (aao.org)
  • More specifically, positive lenses, which bring the focus in front of the retina for a relaxed emmetropic eye (imposed myopic defocus), result in slowed ocular growth while negative lenses, which place the focus behind the retina in a relaxed emmetropic eye (imposed hyperopic defocus), result in accelerated ocular growth. (arvojournals.org)
  • It is equal to 1/ k in dioptres, where k is the distance between the far point and either the spectacle plane ( spectacle refraction ), or the principal point of the eye, or the refracting surface of the reduced eye ( ocular refraction ), in metres. (thefreedictionary.com)
  • This module focuses on clinical techniques of objective and subjective refraction using trial lenses on trial frame as well as with the phoropter. (np.edu.sg)
  • Data were analyzed for differential expression of single genes, and Gene Set Enrichment Analysis (GSEA) was used to identify gene sets correlated with ocular axial length and refraction across lens groups. (frontiersin.org)
  • We found that high myopic patients with the non-VL transmitting pIOLs implanted are almost two times more myopic in the change of refraction and four times longer in the change of axial length, compared to those implanted with the VL transmitting pIOLs. (nature.com)
  • Take anatomical or functional ocular measurements of the eye or surrounding tissue, such as axial length measurements. (ccp.edu)
  • Cross-sectional ocular biometric data were collected to quantify accommodative axial length changes from early adulthood to advanced presbyopia (n=72). (bl.uk)
  • Accommodative axial length elongation significantly attenuated during presbyopia, which was consistent with a significant increase in ocular rigidity during presbyopia. (bl.uk)
  • Learn about anatomy and physiology, geometrical & physical optics, refraction and ophthalmic optics and dispensing. (np.edu.sg)
  • Subjects with previous ocular surgeries or any coexisting ocular diseases such as corneal pathology were excluded. (escrs.org)
  • Lenticular changes appear to be determinant of changes in refraction during incipient presbyopia. (bl.uk)
  • The refraction brought about by the refractive media of the eye (cornea, aqueous humor, crystalline lens, vitreous body). (thefreedictionary.com)
  • To compare the axial lengths, anterior chamber depths, and keratometric measurements and to predict postoperative refractions of Dual Scheimpflug analyzer Galilei G6(R) and intra ocular lens (IOL) Master(R). (bvsalud.org)
  • Ocular dominance is an important consideration in predicting patient satisfaction with monovision correction in cataract surgery refractive surgery, also laser eye surgery, and contact lens wear. (wikipedia.org)
  • Total rrfractive error of the eye includes corneal refraction ( glasses prescription based on corneal shape ) and lens refractive error . (healthtap.com)
  • where d is the thickness of the lens, n the index of refraction of the lens, F 1 the power of the front surface, F 2 the power of the back surface and F e the equivalent power. (thefreedictionary.com)
  • Performs intra-ocular lens calculations using an IOL Master or equivalent device. (federaljobsearch.com)
  • The threshold for consistent responses to positive lens defocus in tree shrew was between +4 and +6 D. The results will enable targeted investigation of the efficacy of positive lens defocus in inhibiting myopic ocular growth. (arvojournals.org)
  • In the most frequently studied model of ocular growth and refractive development, the chick, it has been demonstrated that the rate of ocular growth can be manipulated to bring about compensation for a wide range of lens-induced defocus (−10 D to +15 D), predominantly brought about by altered axial ocular dimensions. (arvojournals.org)
  • The primary aim of this thesis was to investigate the in vivo ocular morphological and contractile changes occurring within the accommodative apparatus prior to the onset of presbyopia, with particular reference to ciliary muscle changes with age and the origin of a myopic shift in refraction during incipient presbyopia. (bl.uk)
  • or =1 D hyperopic anisometropia and ocular disease affecting vision. (nih.gov)
  • During normal development, the refractions of WT mice started at 5.36 ± 0.68 diopters (D) and became more hyperopic before plateauing at 7.78 ± 0.64 D. In contrast, refractions in Gnat1 −/− mice were stable at 7.39 ± 1.22 D across all ages. (arvojournals.org)
  • Hyperopic refractive error diagnosis was confirmed by dry retinoscopic refraction. (escrs.org)
  • A multidiagnostic device is able to provide consistent measurements of refraction and ocular aberrations in healthy eyes. (modernmedicine.com)
  • Mean and standard deviation of refraction, astigmatic power (plus cylinder), axis of astigmatism, and keratometric reading were calculated and compared between groups and correlated with BW and GA in the premature babies. (bmj.com)
  • The cornea is one of several structures in the eye that contributes to refraction. (aapc.com)
  • The ocular biometric measurements and prediction of postoperative refraction using Galilei G6(R) were as accurate as with IOL Master(R). (bvsalud.org)
  • The study of the choroid may promote an understanding of the physiopathology of ocular diseases in which this vascular layer may play an important role and may show that the choroid can serve as an indicator for monitoring changes in various systemic diseases associated with vascular dysfunction. (hindawi.com)
  • Dr. Hong has a strong background in treating ocular eye diseases, geriatric eye care, and refraction. (zocdoc.com)
  • Performs basic refractometry utilizing an auto refraction or habitual glass prescription in the phoropter. (federaljobsearch.com)
  • Retinal photography, auto-refraction and adminstering field testing. (optiboard.com)
  • Motor ocular dominance was determined using the hole-in-the-card test. (biomedsearch.com)
  • CONCLUSIONS: Gender appears to be a factor when testing ocular dominance but not SE refractive error. (biomedsearch.com)
  • Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other. (wikipedia.org)
  • In a 1998 study of professional baseball players, hand-ocular dominance patterns did not show an effect on batting average or ERA. (wikipedia.org)
  • It is an objective test of ocular dominance. (wikipedia.org)
  • Corneal biomechanics parameters: CH, CRF, IOPg, IOPcc as well as CCT were measured using Ocular Response Analyzer by Reichert, NY. (escrs.org)
  • Numerous studies have been carried out to find out the relations of refractive error and ocular biometric measures with birth parameters in preterm or low birth weight child at birth and in the long term [ 6 , 9 - 13 ]. (hindawi.com)
  • A few studies investigated the association of birth parameters and refraction or biometric parameters in the general population of children [ 14 - 16 ]. (hindawi.com)
  • This study describes peripheral refraction and its associations with central refractive error in young Singapore Chinese children. (arvojournals.org)
  • Peripheral refraction was measured after pupil dilation using an infrared autorefractor. (arvojournals.org)
  • However, recent interest into understanding the influence of peripheral refraction on central refractive error has increased, and studies suggest that peripheral refractive error may play a key role in refractive eye development. (arvojournals.org)
  • Pretreatment ocular growth rates and baseline peripheral refraction accounted for 40% of the induced refraction and axial growth rate changes. (nih.gov)
  • We investigated whether transfer from SL or ML to BL leads to recuperation of ocular refraction and anatomy of developing guinea pigs. (arvojournals.org)
  • Social, demographic, and ocular parameters were similar in the 2 groups. (nih.gov)
  • To compare refraction and keratometry readings between premature and term babies at 40 weeks' postconceptional age (PCA), and the possible effect of birth weight (BW) and gestational age (GA) on ocular parameters. (bmj.com)
  • Noninvasive techniques are used to assess arterial and venous dimensions and flow parameters, ocular pressure and structure, and changes in intracranial pressure. (nasa.gov)
  • Although most researchers agree that people's refractive status is in large part genetically determined, a growing body of evidence shows that visual experiences early in life may affect ocular growth and eventual refractive status. (bmj.com)
  • The anatomical relationships of the orbital contents including the extra-ocular muscles, orbital nerves, orbital blood vessels and ocular adnexa are described. (np.edu.sg)
  • Visual acuity, refraction, and deviation angle were determined in all patients preoperatively and postoperatively, and stereoacuity was measured postoperatively. (biomedsearch.com)
  • On-axis refraction (central refractive error) is typically regarded as the primary determinant of visual acuity and is the research topic of most studies on refractive errors. (arvojournals.org)
  • Problems with hand-to-eye coordination, reaction time to visual stimulus, and accurate tracking (eye following) ability can indicate problems with ocular movement. (campuseyegroup.com)
  • Digital eye strain (DES), also known as computer vision syndrome, encompasses a range of ocular and visual symptoms, and estimates suggest its prevalence may be 50% or more among computer users. (bmj.com)
  • To investigate the age-related development of refractive errors and changes of visual acuity (VA), and the systemic and ocular anomalies in Japanese children and young adults with Down syndrome (DS). (dovepress.com)
  • In addition, we evaluated the possible relation of birth weight (BW) and gestational age (GA) in premature infants with their refraction and keratometry findings. (bmj.com)
  • Ocular findings in Loeys-Dietz syndrome. (medworm.com)
  • The objective of the ocular tests was to monitor subjects' ocular health during the study. (nasa.gov)
  • An additional objective was to assess the correlation between choroidal thickness, ocular proptosis, and thyroid function testing. (hindawi.com)
  • where F 1 and F 2 are the powers of the lenses or surfaces comprising the system, d is the distance between the two and n the index of refraction of the intervening medium. (thefreedictionary.com)
  • Induced defocus from optical lenses has been demonstrated, in a variety of vertebrate species, to result in altered ocular growth in an attempt by the eye to attain functional emmetropia. (arvojournals.org)
  • There is significant reduction in the standard deviation, owing to a decrease in variability of refraction (which results in the leptokurtic shift in distribution) (Figure 4). (aao.org)
  • Reduction in standard deviation due to decreased variability in refraction between 1 and 3 years of age (leptokurtic shift). (aao.org)
  • 1.- Prevalence of ocular abnormalities in adults with Down syndrome in Hong Kong. (issuu.com)