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 normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.
Refraction of LIGHT effected by the media of the EYE.
The turning inward of the lines of sight toward each other.
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.
The aperture in the iris through which light passes.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
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.
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.
A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
Images seen by one eye.
Surgical removal of a section of the iris.
The condition of where images are correctly brought to a focus on the retina.
The evacuation of food from the stomach into the duodenum.
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.
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)
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.
The blending of separate images seen by each eye into one composite image.
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 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 front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.
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.
Processes and properties of the EYE as a whole or of any of its parts.
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.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
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.
One of the MUSCARINIC ANTAGONISTS with pharmacologic action similar to ATROPINE and used mainly as an ophthalmic parasympatholytic or mydriatic.
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.
Agents causing contraction of the pupil of the eye. Some sources use the term miotics only for the parasympathomimetics but any drug used to induce miosis is included here.
Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.
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)
Term generally used to describe complaints related to refractive error, ocular muscle imbalance, including pain or aching around the eyes, burning and itchiness of the eyelids, ocular fatigue, and headaches.
An inflatable device implanted in the stomach as an adjunct to therapy of morbid obesity. Specific types include the silicone Garren-Edwards Gastric Bubble (GEGB), approved by the FDA in 1985, and the Ballobes Balloon.
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.
A condition of an inequality of refractive power of the two eyes.
The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)
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.
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)
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)
Tumors or cancer of the EYE.
A series of tests used to assess various functions of the eyes.
Asymmetries in the topography and refractive index of the corneal surface that affect visual acuity.
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)
Presence of an intraocular lens after cataract extraction.
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.
That portion of the electromagnetic spectrum usually sensed as heat. Infrared wavelengths are longer than those of visible light, extending into the microwave frequencies. They are used therapeutically as heat, and also to warm food in restaurants.
Abnormal distention of the STOMACH due to accumulation of gastric contents that may reach 10 to 15 liters. Gastric dilatation may be the result of GASTRIC OUTLET OBSTRUCTION; ILEUS; GASTROPARESIS; or denervation.
Voluntary or reflex-controlled movements of 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)
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.
The 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.
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)
Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.
The use of statistical and mathematical methods to analyze biological observations and phenomena.
Perception of three-dimensionality.
The pressure of the fluids in the eye.
Tuberculous infection of the eye, primarily the iris, ciliary body, and choroid.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
Artificial implanted lenses.
The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.
A parasympatholytic anticholinergic used solely to obtain mydriasis or cycloplegia.
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).
The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.
Impaired digestion, especially after eating.
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 thin noncellular outer covering of the CRYSTALLINE LENS composed mainly of COLLAGEN TYPE IV and GLYCOSAMINOGLYCANS. It is secreted by the embryonic anterior and posterior epithelium. The embryonic posterior epithelium later disappears.
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).
Health care provided to individuals.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
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.
Chronic delayed gastric emptying. Gastroparesis may be caused by motor dysfunction or paralysis of STOMACH muscles or may be associated with other systemic diseases such as DIABETES MELLITUS.
Descriptive anatomy based on three-dimensional imaging (IMAGING, THREE-DIMENSIONAL) of the body, organs, and structures using a series of computer multiplane sections, displayed by transverse, coronal, and sagittal analyses. It is essential to accurate interpretation by the radiologist of such techniques as ultrasonic diagnosis, MAGNETIC RESONANCE IMAGING, and computed tomography (TOMOGRAPHY, X-RAY COMPUTED). (From Lane & Sharfaei, Modern Sectional Anatomy, 1992, Preface)
Paid work for mentally or physically disabled persons, taking place in regular or normal work settings. It may be competitive employment (work that pays minimum wage) or employment with subminimal wages in individualized or group placement situations. It is intended for persons with severe disabilities who require a range of support services to maintain employment. Supported employment differs from SHELTERED WORKSHOPS in that work in the latter takes place in a controlled working environment. Federal regulations are authorized and administered by the U.S. Department of Education, Office of Special Education and Rehabilitative Services.
The immune responses of a host to a graft. A specific response is GRAFT REJECTION.
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.
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.
Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.
The teaching or training of those individuals with hearing disability or impairment.
A visual symptom in which a single object is perceived by the visual cortex as two objects rather than one. Disorders associated with this condition include REFRACTIVE ERRORS; STRABISMUS; OCULOMOTOR NERVE DISEASES; TROCHLEAR NERVE DISEASES; ABDUCENS NERVE DISEASES; and diseases of the BRAIN STEM and OCCIPITAL LOBE.
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.
Conjunctival diseases refer to a broad range of disorders that affect the conjunctiva, the mucous membrane covering the inner surface of the eyelids and the outer layer of the eyeball, causing symptoms such as redness, itching, irritation, discharge, and/or inflammation.
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.
'Reading' in a medical context often refers to the act or process of a person interpreting and comprehending written or printed symbols, such as letters or words, for the purpose of deriving information or meaning from them.
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)
The absence or restriction of the usual external sensory stimuli to which the individual responds.
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.
Conjunctivitis is an inflammation or infection of the conjunctiva, the transparent membrane that lines the inner surface of the eyelids and covers the white part of the eye, resulting in symptoms such as redness, swelling, itching, burning, discharge, and increased sensitivity to light.
Abnormally low intraocular pressure often related to chronic inflammation (uveitis).
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.
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.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
A potent, long-acting cholinesterase inhibitor used as a miotic in the treatment of glaucoma.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye.
Involuntary movements of the eye that are divided into two types, jerk and pendular. Jerk nystagmus has a slow phase in one direction followed by a corrective fast phase in the opposite direction, and is usually caused by central or peripheral vestibular dysfunction. Pendular nystagmus features oscillations that are of equal velocity in both directions and this condition is often associated with visual loss early in life. (Adams et al., Principles of Neurology, 6th ed, p272)
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
The act of knowing or the recognition of a distance by recollective thought, or by means of a sensory process which is under the influence of set and of prior experience.
Diseases of the cornea.
The time frame after a meal or FOOD INTAKE.
The hospital department responsible for the administration and provision of diagnostic and therapeutic services for the cancer patient.
Professional society representing the field of dentistry.
Congenital absence of or defects in structures of the eye; may also be hereditary.
A series of actions, sometimes symbolic actions which may be associated with a behavior pattern, and are often indispensable to its performance.
Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.
The distance between the anterior and posterior poles of the eye, measured either by ULTRASONOGRAPHY or by partial coherence interferometry.
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.
A species of the genus MACACA which typically lives near the coast in tidal creeks and mangrove swamps primarily on the islands of the Malay peninsula.
Anxiety experienced by an individual upon separation from a person or object of particular significance to the individual.
Examination of the interior of the eye with an ophthalmoscope.
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)
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
The superior portion of the body of the stomach above the level of the cardiac notch.
A slowly hydrolyzed muscarinic agonist with no nicotinic effects. Pilocarpine is used as a miotic and in the treatment of glaucoma.
A species of baboon in the family CERCOPITHECIDAE, which has a well-studied trilevel social structure consisting of troops, bands, and clans.
Shiny, flexible bands of fibrous tissue connecting together articular extremities of bones. They are pliant, tough, and inextensile.
The storing or preserving of video signals for television to be played back later via a transmitter or receiver. Recordings may be made on magnetic tape or discs (VIDEODISC RECORDING).
A system of hand gestures used for communication by the deaf or by people speaking different languages.
The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)
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)
Elements of limited time intervals, contributing to particular results or situations.
Devices, not affixed to the body, designed to help persons having musculoskeletal or neuromuscular disabilities to perform activities involving movement.
Application of pharmaceutically active agents on the tissues of the EYE.
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.
Infections in the inner or external eye caused by microorganisms belonging to several families of bacteria. Some of the more common genera found are Haemophilus, Neisseria, Staphylococcus, Streptococcus, and Chlamydia.
A pupillary abnormality characterized by a poor pupillary light reaction, reduced accommodation, iris sector palsies, an enhanced pupillary response to near effort that results in a prolonged, "tonic" constriction, and slow pupillary redilation. This condition is associated with injury to the postganglionic parasympathetic innervation to the pupil. (From Miller et al., Clinical Neuro-Ophthalmology, 4th ed, pp492-500)
The motor activity of the GASTROINTESTINAL TRACT.
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).
Bilateral dissection of the abdominal branches of the vagus nerve. It is used frequently in the surgical management of duodenal and gastric ulcers, as well as in physiologic studies of gastrointestinal secretion and motility.
A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
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.
Devices for examining the interior of the eye, permitting the clear visualization of the structures of the eye at any depth. (UMDNS, 1999)
Unequal pupil size, which may represent a benign physiologic variant or a manifestation of disease. Pathologic anisocoria reflects an abnormality in the musculature of the iris (IRIS DISEASES) or in the parasympathetic or sympathetic pathways that innervate the pupil. Physiologic anisocoria refers to an asymmetry of pupil diameter, usually less than 2mm, that is not associated with disease.
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)
An anxiety disorder characterized by recurrent, persistent obsessions or compulsions. Obsessions are the intrusive ideas, thoughts, or images that are experienced as senseless or repugnant. Compulsions are repetitive and seemingly purposeful behavior which the individual generally recognizes as senseless and from which the individual does not derive pleasure although it may provide a release from tension.
The core of the crystalline lens, surrounded by the cortex.
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.
Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.
Each of the upper and lower folds of SKIN which cover the EYE when closed.
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.
The science or philosophy of law. Also, the application of the principles of law and justice to health and medicine.

Latrunculin-A causes mydriasis and cycloplegia in the cynomolgus monkey. (1/610)

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)

Tonic accommodation, age, and refractive error in children. (2/610)

PURPOSE: An association between tonic accommodation, the resting accommodative position of the eye in the absence of a visually compelling stimulus, and refractive error has been reported in adults and children. In general, myopes have the lowest (or least myopic) levels of tonic accommodation. The purpose in assessing tonic accommodation was to evaluate it as a predictor of onset of myopia. METHODS: Tonic accommodation was measured in children enrolled in the Orinda Longitudinal Study of Myopia using an infrared autorefractor (model R-1; Canon, Lake Success, NY) while children viewed an empty lit field or a dark field with a fixation spot projected in Maxwellian view. Children aged 6 to 15 years were measured from 1991 through 1994 (n = 714, 766, 771, and 790 during the 4 years, successively). Autorefraction provided refractive error and tonic accommodation data, and videophakometry measured crystalline lens curvatures. RESULTS: Comparison of the two methods for measuring tonic accommodation shows a significant effect of age across all years of testing, with the lit empty-field test condition yielding higher levels of tonic accommodation compared with the dark-field test condition in children aged 6 through 11 years. For data collected in 1994, mean (+/-SD) tonic accommodation values for the lit empty-field condition were significantly lower in myopes, intermediate in emmetropes, and highest in hyperopes (1.02 +/- 1.18 D, 1.92 +/- 1.59 D, and 2.25 +/- 1.78 D, respectively; Kruskal-Wallis test, P < 0.001; between-group testing shows each group is different from the other two). Age, refractive error, and Gullstrand lens power were significant terms in a multiple regression model of tonic accommodation (R2 = 0.18 for 1994 data). Lower levels of tonic accommodation for children entering the study in the first or third grades were not associated with an increased risk of the onset of myopia, whether measured in the lit empty-field test condition (relative risk = 0.90; 95% confidence interval = 0.75, 1.08), or the dark-field test condition (relative risk = 0.83; 95% confidence interval = 0.60, 1.14). CONCLUSIONS: This is the first study to document an association between age and tonic accommodation. The known association between tonic accommodation and refractive error was confirmed and it was shown that an ocular component, Gullstrand lens power, also contributed to the tonic accommodation level. There does not seem to be an increased risk of onset of juvenile myopia associated with tonic accommodation.  (+info)

Human dynamic closed-loop accommodation augmented by sympathetic inhibition. (3/610)

PURPOSE: A ciliary alpha-adrenoceptor accommodative effect has been proposed, caused by a small population of alpha1-inhibitory receptors in excised human ciliary muscle. This study was intended to investigate the effect on the closed-loop dynamic accommodative process of modulating alpha1-adrenoceptor activity by topical instillation of the alpha1-adrenergic agonist, phenylephrine hydrochloride. METHODS: A group of 10 visually normal subjects viewed a photopic (30 candela/m2) high-contrast Maltese cross, which was modulated sinusoidally (0.05-0.6Hz) and stepwise over a 2-D range (2-4 D). Monocular temporal accommodation responses were measured using a continuously recording dynamic tracking infrared optometer under two trial conditions: after instillation of saline control solution and 50 minutes subsequent to the instillation of 0.27 microl 0.4% benoxinate hydrochloride and 0.27 microl 2.5% phenylephrine hydrochloride. Pupil size and accommodative amplitude were measured at 90-second intervals for 50 minutes after drug instillation. All accommodative measurements were recorded through a fixed 4-mm pupil. RESULTS: A significant reduction in accommodative amplitude (11%; P < 0.05) was recorded, whereas pupil size showed a significant increase (33%; P < 0.05). No significant change in step-response dynamics was observed. However, phenylephrine hydrochloride caused a significant increase in accommodative gain in the low and midtemporal frequency ranges compared with the effect of a saline control treatment. No significant variation in phase lag was observed. CONCLUSIONS: For the first time in humans, this study shows that augmentation of the alpha1-inhibitory sympathetic contribution results in increased accommodative gain at low and midtemporal frequencies, which is consistent with findings in animal studies.  (+info)

Age-related changes in human ciliary muscle and lens: a magnetic resonance imaging study. (4/610)

PURPOSE: To use high-resolution magnetic resonance (MR) images of the eye to directly measure the relationship between ciliary muscle contraction and lens response with advancing age. METHODS: A General Electric, 1.5-Tesla MR imager and a custom-designed eye imaging coil were used to collect high-resolution MR images from 25 subjects, 22 through 83 years of age. A nonmagnetic binocular stimulus apparatus was used to induce both relaxed accommodation (0.1 diopter [D]) and strong accommodative effort (8.0 D). Measurements of the ciliary muscle ring diameter (based on the inner apex), lens equatorial diameter, and lens thickness were derived from the MR images. RESULTS: Muscle contraction is present in all subjects and reduces only slightly with advancing age. A decrease in the diameter of the unaccommodated ciliary muscle ring was highly correlated with advancing age. Lens equatorial diameter does not correlate with age for either accommodative state. Although unaccommodated lens thickness (i.e., lens minor axis length) increases with age, the thickness of the lens under accommodative effort is only modestly age-dependent. CONCLUSIONS: Ciliary muscle contractile activity remains active in all subjects. A decrease in the unaccommodated ciliary muscle diameter, along with the previously noted increase in lens thickness (the "lens paradox"), demonstrates the greatest correlation with advancing age. These results support the theory that presbyopia is actually the loss in ability to disaccommodate due to increases in lens thickness, the inward movement of the ciliary ring, or both.  (+info)

Characteristics of accommodation toward apparent depth. (5/610)

This paper deals with characteristics of accommodation evoked by perceived depth sensation and the dynamic relationship between accommodation and vergence, applying newly developed optical measurement apparatuses. A total of five subjects looked at three different two-dimensional stimuli and two different three-dimensional stimuli; namely a real image and a stereoscopic image. With regard to the two-dimensional stimuli, a manifest accommodation without any accompanying vergence was found because of an apparent depth sensation even though the target distance was kept constant. With regard to the three-dimensional stimuli, larger accommodation and clear vergence were evoked because of binocular parallax and a stronger depth sensation. As for the stereoscopic image, a manifest overshoot (the accommodation peaked first and receded considerably) was found while the vergence remained constant. On the other hand, the overshoot of accommodation was smaller when subjects were watching the real image. These results reveal that brain depth perception has a higher effect on accommodation than expected. The relationship of accommodation and vergence toward the stereoscopic image suggests a reason why severe visual fatigue is commonly experienced by many viewers using stereoscopic displays. It has also paved the way for the numerical analysis of the oculomotor triad system.  (+info)

Optics of the developing fish eye: comparisons of Matthiessen's ratio and the focal length of the lens in the black bream Acanthopagrus butcheri (Sparidae, Teleostei). (6/610)

Matthiessen's ratio (distance from centre of lens to retina:lens radius) was measured in developing black bream, Acanthopagrus butcheri (Sparidae, Teleostei). The value decreased over the first 10 days post-hatch from 3.6 to 2.3 along the nasal and from four to 2.6 along temporal axis. Coincidentally, there was a decrease in the focal ratio of the lens (focal length:lens radius). Morphologically, the accommodatory retractor lentis muscle appeared to become functional between 10-12 days post-hatch. The results suggest that a higher focal ratio compensates for the relatively high Matthiessen's ratio brought about by constraints of small eye size during early development. Combined with differences in axial length, this provides a means for larval fish to focus images from different distances prior to the ability to accommodate.  (+info)

The growing eye: an autofocus system that works on very poor images. (7/610)

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)

Mechanics of accommodation of the human eye. (8/610)

The classical Helmholtz theory of accommodation has, over the years, not gone unchallenged and most recently has been opposed by Schachar at al. (1993) (Annals of Ophthalmology, 25 (1) 5-9) who suggest that increasing the zonular tension increases rather than decreases the power of the lens. This view is supported by a numerical analysis of the lens based on a linearised form of the governing equations. We propose in this paper an alternative numerical model in which the geometric non-linear behaviour of the lens is explicitly included. Our results differ from those of Schachar et al. (1993) and are consistent with the classical Helmholtz mechanism.  (+info)

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

Presbyopia is a age-related eye condition, typically occurring after the age of 40, where the lens of the eye loses its flexibility and makes it difficult to focus on near objects. This results in blurred vision when reading, sewing or focusing on other close-up tasks. It's a natural part of the aging process and is not a disease. Corrective measures such as reading glasses, bifocals, multifocal lenses or contact lenses, or refractive surgery can help manage this condition.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

An iridectomy is a surgical procedure that involves removing a small portion of the iris, which is the colored part of the eye. This procedure is typically performed to treat conditions such as closed-angle glaucoma or to prevent the development of acute angle closure glaucoma. By creating an opening in the iris, the surgery helps to improve the flow of fluid within the eye and reduce pressure inside the eye. It is usually done using a laser (laser iridectomy) or with surgical instruments (surgical iridectomy).

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

Gastric emptying is the process by which the stomach empties its contents into the small intestine. In medical terms, it refers to the rate and amount of food that leaves the stomach and enters the duodenum, which is the first part of the small intestine. This process is regulated by several factors, including the volume and composition of the meal, hormonal signals, and neural mechanisms. Abnormalities in gastric emptying can lead to various gastrointestinal symptoms and disorders, such as gastroparesis, where the stomach's ability to empty food is delayed.

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

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

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

Ocular toxoplasmosis is an inflammatory eye disease caused by the parasitic infection of Toxoplasma gondii in the eye's retina. It can lead to lesions and scarring in the retina, resulting in vision loss or impairment. The severity of ocular toxoplasmosis depends on the location and extent of the infection in the eye. In some cases, it may cause only mild symptoms, while in others, it can result in severe damage to the eye. Ocular toxoplasmosis is usually treated with medications that target the Toxoplasma gondii parasite, such as pyrimethamine and sulfadiazine, often combined with corticosteroids to reduce inflammation.

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

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

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

Ocular motility disorders refer to a group of conditions that affect the movement of the eyes. These disorders can result from nerve damage, muscle dysfunction, or brain injuries. They can cause abnormal eye alignment, limited range of motion, and difficulty coordinating eye movements. Common symptoms include double vision, blurry vision, strabismus (crossed eyes), nystagmus (involuntary eye movement), and difficulty tracking moving objects. Ocular motility disorders can be congenital or acquired and may require medical intervention to correct or manage the condition.

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

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

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

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

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

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

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

Ocular albinism is a type of albinism that primarily affects the eyes. It is a genetic disorder characterized by the reduction or absence of melanin, the pigment responsible for coloring the skin, hair, and eyes. In ocular albinism, melanin production is deficient in the eyes, leading to various eye abnormalities.

The main features of ocular albinism include:

1. Nystagmus: Rapid, involuntary back-and-forth movement of the eyes.
2. Iris transillumination: The iris appears translucent due to the lack of pigment, allowing light to pass through easily. This can be observed using a light source shone into the eye.
3. Foveal hypoplasia: Underdevelopment or absence of the fovea, a small pit in the retina responsible for sharp, central vision.
4. Photophobia: Increased sensitivity to light due to the lack of pigment in the eyes.
5. Strabismus: Misalignment of the eyes, which can result in double vision or lazy eye.
6. Reduced visual acuity: Decreased ability to see clearly, even with corrective lenses.

Ocular albinism is typically inherited as an X-linked recessive trait, meaning it primarily affects males, while females can be carriers of the condition. However, there are also autosomal recessive forms of ocular albinism that can affect both males and females equally. Treatment for ocular albinism usually involves managing symptoms with corrective lenses, low-vision aids, and vision therapy to improve visual skills.

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

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

In anatomical terms, the stomach is a muscular, J-shaped organ located in the upper left portion of the abdomen. It is part of the gastrointestinal tract and plays a crucial role in digestion. The stomach's primary functions include storing food, mixing it with digestive enzymes and hydrochloric acid to break down proteins, and slowly emptying the partially digested food into the small intestine for further absorption of nutrients.

The stomach is divided into several regions, including the cardia (the area nearest the esophagus), the fundus (the upper portion on the left side), the body (the main central part), and the pylorus (the narrowed region leading to the small intestine). The inner lining of the stomach, called the mucosa, is protected by a layer of mucus that prevents the digestive juices from damaging the stomach tissue itself.

In medical contexts, various conditions can affect the stomach, such as gastritis (inflammation of the stomach lining), peptic ulcers (sores in the stomach or duodenum), gastroesophageal reflux disease (GERD), and stomach cancer. Symptoms related to the stomach may include abdominal pain, bloating, nausea, vomiting, heartburn, and difficulty swallowing.

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

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

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

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

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

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

Tropicamide is a muscarinic antagonist, which is a type of drug that blocks the action of acetylcholine in the body. In particular, it blocks the muscarinic receptors found in the eye, which results in pupil dilation (mydriasis) and paralysis of the ciliary muscle (cycloplegia).

Tropicamide is commonly used in ophthalmology as a diagnostic aid during eye examinations. It is often instilled into the eye to dilate the pupil, which allows the eye care professional to more easily examine the back of the eye and assess conditions such as cataracts, glaucoma, or retinal disorders. The cycloplegic effect of tropicamide also helps to relax the accommodation reflex, making it easier to measure the refractive error of the eye and determine the appropriate prescription for eyeglasses or contact lenses.

It is important to note that tropicamide can cause temporary blurring of vision and sensitivity to light, so patients should be advised not to drive or operate heavy machinery until the effects of the medication have worn off.

Aniseikonia is a medical term that refers to a condition where there is a significant difference in the size or shape of the images perceived by each eye. This occurs when there is a disproportionate amount of magnification or minification between the two eyes, leading to a mismatch in the visual perception of objects' size and shape.

Aniseikonia can result from various factors, including anisometropia (a significant difference in the refractive power between the two eyes), cataract surgery, corneal irregularities, or retinal diseases. It can cause symptoms such as eyestrain, headaches, and difficulty with depth perception, reading, and overall visual comfort.

Treatment for aniseikonia typically involves correcting the underlying refractive error with prescription lenses, prisms, or contact lenses. In some cases, surgical intervention may be necessary to address any structural issues causing the condition.

Miotics, also known as parasympathomimetics or cholinergic agents, are a class of medications that stimulate the parasympathetic nervous system. They work by activating muscarinic receptors, which are found in various organs throughout the body, including the eye. In the eye, miotics cause contraction of the circular muscle of the iris, resulting in pupillary constriction (miosis). This action can help to reduce intraocular pressure in patients with glaucoma.

Miotics may also have other effects on the eye, such as accommodation (focusing) and decreasing the production of aqueous humor. Some examples of miotics include pilocarpine, carbachol, and ecothiopate. It's important to note that the use of miotics can have side effects, including blurred vision, headache, and brow ache.

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

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

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

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

Asthenopia is a medical term that refers to eye fatigue or discomfort, often accompanied by headache and blurred vision. It is typically caused by prolonged visual tasks such as reading, writing, or using a computer, especially in conditions of poor lighting or when focusing on a single object for a long time. Other factors that can contribute to asthenopia include uncorrected vision problems, eye strain, and dry eyes. Resting the eyes and addressing any underlying vision issues can help alleviate symptoms of asthenopia.

A gastric balloon is a medical device that is temporarily inserted into the stomach to help with weight loss. It is typically used for individuals who are moderately overweight and have not been able to lose weight through diet and exercise alone. The procedure involves placing a deflated balloon into the stomach through the mouth, then filling it with saline solution once it's in place. This reduces the amount of space available in the stomach for food, leading to a feeling of fullness and reduced appetite. After several months, the balloon is removed through an endoscopic procedure. It's important to note that gastric balloons are not a permanent solution to obesity and should be used as part of a comprehensive weight loss plan that includes diet, exercise, and behavior modification.

Aberrometry is a medical diagnostic technique used to measure the amount and type of aberration or distortion in the optical system of the eye. It is often used to evaluate the quality of vision, particularly in cases where traditional methods of measuring visual acuity are not sufficient.

During an aberrometry test, the patient looks into a specialized instrument called a wavefront sensor while a series of light patterns are projected onto the retina. The sensor then measures how the light is distorted as it passes through the eye's optical system, including the cornea and lens. This information is used to create a detailed map of the eye's aberrations, which can help doctors identify any irregularities that may be contributing to visual symptoms such as blurred vision, glare, or halos around lights.

Aberrometry is often used in conjunction with other diagnostic tests to evaluate patients who are considering refractive surgery, such as LASIK or PRK. By identifying any abnormalities in the eye's optical system, doctors can determine whether a patient is a good candidate for surgery and make more informed decisions about how to proceed with treatment.

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

Ocular adaptation is the ability of the eye to adjust and accommodate to changes in visual input and lighting conditions. This process allows the eye to maintain a clear and focused image over a range of different environments and light levels. There are several types of ocular adaptation, including:

1. Light Adaptation: This refers to the eye's ability to adjust to different levels of illumination. When moving from a dark environment to a bright one, the pupils constrict to let in less light, and the sensitivity of the retina decreases. Conversely, when moving from a bright environment to a dark one, the pupils dilate to let in more light, and the sensitivity of the retina increases.
2. Dark Adaptation: This is the process by which the eye adjusts to low light conditions. It involves the dilation of the pupils and an increase in the sensitivity of the rods (specialised cells in the retina that are responsible for vision in low light conditions). Dark adaptation can take several minutes to occur fully.
3. Color Adaptation: This refers to the eye's ability to adjust to changes in the color temperature of light sources. For example, when moving from a room lit by incandescent light to one lit by fluorescent light, the eye may need to adjust its perception of colors to maintain accurate color vision.
4. Accommodation: This is the process by which the eye changes focus from distant to near objects. The lens of the eye changes shape to bend the light rays entering the eye and bring them into sharp focus on the retina.

Overall, ocular adaptation is an essential function that allows us to see clearly and accurately in a wide range of environments and lighting conditions.

Ocular dominance refers to the preference of one eye over the other in terms of visual perception and processing. In other words, it is the tendency for an individual to rely more heavily on the input from one particular eye when interpreting visual information. This can have implications in various visual tasks such as depth perception, aiming, and targeting.

Ocular dominance can be determined through a variety of tests, including the Miles test, the Porta test, or simply by observing which eye a person uses to align a visual target. It is important to note that ocular dominance does not necessarily indicate any sort of visual impairment or deficit; rather, it is a normal variation in the way that visual information is processed by the brain.

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

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

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

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

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

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

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

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

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

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

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

Vision tests are a series of procedures used to assess various aspects of the visual system, including visual acuity, accommodation, convergence, divergence, stereopsis, color vision, and peripheral vision. These tests help healthcare professionals diagnose and manage vision disorders, such as nearsightedness, farsightedness, astigmatism, amblyopia, strabismus, and eye diseases like glaucoma, cataracts, and macular degeneration. Common vision tests include:

1. Visual acuity test (Snellen chart or letter chart): Measures the sharpness of a person's vision at different distances.
2. Refraction test: Determines the correct lens prescription for glasses or contact lenses by assessing how light is bent as it passes through the eye.
3. Color vision test: Evaluates the ability to distinguish between different colors and color combinations, often using pseudoisochromatic plates or Ishihara tests.
4. Stereopsis test: Assesses depth perception and binocular vision by presenting separate images to each eye that, when combined, create a three-dimensional effect.
5. Cover test: Examines eye alignment and the presence of strabismus (crossed eyes or turned eyes) by covering and uncovering each eye while observing eye movements.
6. Ocular motility test: Assesses the ability to move the eyes in various directions and coordinate both eyes during tracking and convergence/divergence movements.
7. Accommodation test: Evaluates the ability to focus on objects at different distances by using lenses, prisms, or dynamic retinoscopy.
8. Pupillary response test: Examines the size and reaction of the pupils to light and near objects.
9. Visual field test: Measures the peripheral (side) vision using automated perimetry or manual confrontation techniques.
10. Slit-lamp examination: Inspects the structures of the front part of the eye, such as the cornea, iris, lens, and anterior chamber, using a specialized microscope.

These tests are typically performed by optometrists, ophthalmologists, or other vision care professionals during routine eye examinations or when visual symptoms are present.

Corneal wavefront aberration is a measurement of the irregularities in the shape and curvature of the cornea, which can affect the way light enters the eye and is focused on the retina. A wavefront aberration test uses a device to measure the refraction of light as it passes through the cornea and calculates the degree of any distortions or irregularities in the wavefront of the light. This information can be used to guide treatment decisions, such as the prescription for eyeglasses or contact lenses, or the planning of a surgical procedure to correct the aberration.

Corneal wavefront aberrations can be classified into two types: low-order and high-order aberrations. Low-order aberrations include myopia (nearsightedness), hyperopia (farsightedness), and astigmatism, which are common refractive errors that can be easily corrected with glasses or contact lenses. High-order aberrations are more complex irregularities in the wavefront of light that cannot be fully corrected with traditional eyeglasses or contact lenses. These may include coma, trefoil, and spherical aberration, among others.

High-order corneal wavefront aberrations can affect visual quality, causing symptoms such as glare, halos around lights, and decreased contrast sensitivity. They are often associated with conditions that cause changes in the shape of the cornea, such as keratoconus or corneal surgery. In some cases, high-order aberrations can be corrected with specialized contact lenses or refractive surgery procedures such as wavefront-guided LASIK or PRK.

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

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

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

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

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

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

Infrared rays are not typically considered in the context of medical definitions. They are a type of electromagnetic radiation with longer wavelengths than those of visible light, ranging from 700 nanometers to 1 millimeter. In the field of medicine, infrared radiation is sometimes used in therapeutic settings for its heat properties, such as in infrared saunas or infrared therapy devices. However, infrared rays themselves are not a medical condition or diagnosis.

Gastric dilatation, also known as stomach dilation or distention, refers to the abnormal enlargement or expansion of the stomach. This condition often occurs when the stomach fills with gas, food, or fluids and is unable to empty properly. Gastric dilatation can be caused by various factors such as overeating, swallowing excessive air, gastroparesis (delayed gastric emptying), intestinal obstruction, or certain medical conditions like hiatal hernia or pregnancy.

In severe cases, gastric dilatation may lead to gastric volvulus, where the stomach twists on itself, cutting off its blood supply and leading to ischemia and necrosis of the stomach tissue. This is a life-threatening condition that requires immediate medical attention. Symptoms of gastric dilatation include abdominal pain, bloating, vomiting, loss of appetite, and difficulty breathing.

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

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

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

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

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

There are several components of ocular vision, including:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Depth perception is the ability to accurately judge the distance or separation of an object in three-dimensional space. It is a complex visual process that allows us to perceive the world in three dimensions and to understand the spatial relationships between objects.

Depth perception is achieved through a combination of monocular cues, which are visual cues that can be perceived with one eye, and binocular cues, which require input from both eyes. Monocular cues include perspective (the relative size of objects), texture gradients (finer details become smaller as distance increases), and atmospheric perspective (colors become less saturated and lighter in value as distance increases). Binocular cues include convergence (the degree to which the eyes must turn inward to focus on an object) and retinal disparity (the slight difference in the images projected onto the two retinas due to the slightly different positions of the eyes).

Deficits in depth perception can occur due to a variety of factors, including eye disorders, brain injuries, or developmental delays. These deficits can result in difficulties with tasks such as driving, sports, or navigating complex environments. Treatment for depth perception deficits may include vision therapy, corrective lenses, or surgery.

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

Ocular tuberculosis (OTB) is a form of extrapulmonary tuberculosis (TB), which results from the spread of Mycobacterium tuberculosis complex bacteria outside the lungs. In ocular tuberculosis, these bacteria primarily affect the eye and its surrounding structures.

The most common form of OTB is tubercular uveitis, which involves inflammation of the uveal tract (iris, ciliary body, and choroid). Other forms of OTB include:

* Tubercular conjunctivitis: Inflammation of the conjunctiva, the mucous membrane that covers the front part of the eye and lines the inside of the eyelids.
* Tubercular keratitis: Inflammation of the cornea, the transparent outer layer at the front of the eye.
* Tubercular scleritis: Inflammation of the sclera, the white protective coating of the eye.
* Tubercular episcleritis: Inflammation of the episclera, a thin layer of tissue between the conjunctiva and sclera.
* Tubercular dacryoadenitis: Inflammation of the lacrimal gland, which produces tears.
* Tubercular optic neuritis: Inflammation of the optic nerve, which transmits visual information from the eye to the brain.

Diagnosis of OTB can be challenging due to its varied clinical presentations and the need for laboratory confirmation. A definitive diagnosis typically requires the isolation of Mycobacterium tuberculosis from ocular tissues or fluids, which may involve invasive procedures. In some cases, a presumptive diagnosis might be made based on clinical findings, epidemiological data, and response to anti-tuberculous therapy.

Treatment for OTB usually involves a standard anti-tuberculosis regimen consisting of multiple drugs (isoniazid, rifampin, ethambutol, and pyrazinamide) for at least six months. Corticosteroids or other immunosuppressive agents might be used concomitantly to manage inflammation and prevent tissue damage. Close monitoring is essential to ensure treatment adherence, assess response to therapy, and detect potential side effects.

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

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

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

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

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

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

The medical definition of Cyclopentolate is:

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

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

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

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

The oculomotor nerve, also known as the third cranial nerve (CN III), is a motor nerve that originates from the midbrain. It controls the majority of the eye muscles, including the levator palpebrae superioris muscle that raises the upper eyelid, and the extraocular muscles that enable various movements of the eye such as looking upward, downward, inward, and outward. Additionally, it carries parasympathetic fibers responsible for pupillary constriction and accommodation (focusing on near objects). Damage to this nerve can result in various ocular motor disorders, including strabismus, ptosis, and pupillary abnormalities.

Dyspepsia is a medical term that refers to discomfort or pain in the upper abdomen, often accompanied by symptoms such as bloating, nausea, belching, and early satiety (feeling full quickly after starting to eat). It is also commonly known as indigestion. Dyspepsia can have many possible causes, including gastroesophageal reflux disease (GERD), peptic ulcers, gastritis, and functional dyspepsia (a condition in which there is no obvious structural or biochemical explanation for the symptoms). Treatment for dyspepsia depends on the underlying cause.

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

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

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

The crystalline lens of the eye is covered by a transparent, elastic capsule known as the lens capsule. This capsule is made up of collagen and forms the continuous outer layer of the lens. It is highly resistant to both physical and chemical insults, which allows it to protect the lens fibers within. The lens capsule is important for maintaining the shape and transparency of the lens, which are essential for proper focusing of light onto the retina.

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

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

Personal health services refer to healthcare services that are tailored to an individual's specific needs, preferences, and goals. These services can include preventive care, such as vaccinations and screenings, as well as medical treatments for acute and chronic conditions. Personal health services may be provided by a variety of healthcare professionals, including doctors, nurses, physician assistants, and allied health professionals.

The goal of personal health services is to promote the overall health and well-being of the individual, taking into account their physical, mental, emotional, and social needs. This approach recognizes that each person is unique and requires a customized plan of care to achieve their optimal health outcomes. Personal health services may be delivered in a variety of settings, including hospitals, clinics, private practices, and long-term care facilities.

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

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

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

Gastroparesis is a gastrointestinal disorder that affects the stomach's normal motility, resulting in the delayed emptying of food from the stomach into the small intestine. The term "gastroparesis" literally means "stomach paralysis," although the stomach doesn't actually become paralyzed in this condition. Instead, the muscles of the stomach wall become weakened or damaged, leading to a decrease in their ability to contract and push food through the digestive tract effectively.

The causes of gastroparesis can vary, but some common reasons include diabetes (both type 1 and type 2), viral infections, surgery involving the vagus nerve (which controls stomach muscle contractions), certain medications (such as narcotics, antidepressants, and high blood pressure drugs), gastroesophageal reflux disease (GERD), scleroderma, Parkinson's disease, multiple sclerosis, and Amyloidosis.

Symptoms of gastroparesis may include nausea, vomiting, feeling full quickly after starting to eat, bloating, heartburn, abdominal pain, lack of appetite, and unintended weight loss. These symptoms can significantly impact a person's quality of life and make it difficult for them to maintain proper nutrition.

Diagnosis typically involves a thorough medical history, physical examination, and various tests such as upper endoscopy, gastric emptying studies (such as the scintigraphy scan), and manometry to assess stomach muscle function. Treatment options may include dietary modifications, medications to stimulate stomach contractions or reduce symptoms like nausea and vomiting, botulinum toxin injections, electrical stimulation of the stomach muscles, or, in severe cases, feeding tubes or surgery.

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

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

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

Supported employment is a type of vocational rehabilitation service that helps individuals with disabilities to secure and maintain competitive integrated employment in the community. This type of employment provides ongoing support and training in the workplace to help the individual perform their job duties successfully. The goal of supported employment is to assist individuals with disabilities to become as independent as possible and to integrate them into the workforce, while also providing businesses with qualified and reliable employees.

The medical definition of "supported employment" is:

A type of vocational rehabilitation service that provides ongoing support and training in the workplace to help individuals with disabilities secure and maintain competitive integrated employment in the community. Supported employment services may include job placement, job coaching, job training, and other forms of assistance to help the individual perform their job duties successfully and achieve maximum independence and integration in the workforce.

A Host vs Graft Reaction, also known as graft-versus-host disease (GVHD), is a condition that can occur after a transplant of immunocompetent tissue (like bone marrow or peripheral blood stem cells) from a donor (graft) to a recipient (host). It occurs when the transplanted immune cells recognize the recipient's tissues as foreign and mount an immune response against them. This reaction can cause inflammation and damage to various organs, including the skin, liver, and gastrointestinal tract.

GVHD can be acute or chronic, depending on the time of onset and the severity of symptoms. Acute GVHD typically occurs within 100 days of transplantation and is characterized by a rash, diarrhea, and liver dysfunction. Chronic GVHD, which can occur after day 100, is often more severe and can affect multiple organs, leading to fibrosis and organ dysfunction.

Preventing and managing GVHD is an important consideration in transplant medicine, as it can significantly impact the success of the transplant and the recipient's quality of life. Strategies for preventing and treating GVHD include immunosuppressive therapy, T-cell depletion of the graft, and careful matching of donor and recipient to minimize histocompatibility differences.

Timolol is a non-selective beta blocker drug that is primarily used to treat hypertension, angina pectoris, and glaucoma. It works by blocking the action of certain hormones such as epinephrine (adrenaline) on the heart and blood vessels, which helps to lower heart rate, reduce the force of heart muscle contraction, and decrease blood vessel constriction. These effects can help to lower blood pressure, reduce the workload on the heart, and improve oxygen supply to the heart muscle. In glaucoma treatment, timolol reduces the production of aqueous humor in the eye, thereby decreasing intraocular pressure.

The medical definition of Timolol is:

Timolol (tim-oh-lol) is a beta-adrenergic receptor antagonist used to treat hypertension, angina pectoris, and glaucoma. It works by blocking the action of epinephrine on the heart and blood vessels, which results in decreased heart rate, reduced force of heart muscle contraction, and decreased blood vessel constriction. In glaucoma treatment, timolol reduces aqueous humor production, thereby decreasing intraocular pressure. Timolol is available as an oral tablet, solution for injection, and ophthalmic solution.

Topical administration refers to a route of administering a medication or treatment directly to a specific area of the body, such as the skin, mucous membranes, or eyes. This method allows the drug to be applied directly to the site where it is needed, which can increase its effectiveness and reduce potential side effects compared to systemic administration (taking the medication by mouth or injecting it into a vein or muscle).

Topical medications come in various forms, including creams, ointments, gels, lotions, solutions, sprays, and patches. They may be used to treat localized conditions such as skin infections, rashes, inflammation, or pain, or to deliver medication to the eyes or mucous membranes for local or systemic effects.

When applying topical medications, it is important to follow the instructions carefully to ensure proper absorption and avoid irritation or other adverse reactions. This may include cleaning the area before application, covering the treated area with a dressing, or avoiding exposure to sunlight or water after application, depending on the specific medication and its intended use.

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

The medical definition of "Education of Hearing Disabled" refers to the specialized education and teaching methods used for individuals who are deaf or hard of hearing. This type of education is designed to help students with hearing loss develop language, communication, academic, and social skills in a way that meets their unique needs. It can include various approaches such as American Sign Language (ASL), oral/aural methods, cued speech, and cochlear implant rehabilitation. The goal of education for the hearing disabled is to provide students with equal access to learning opportunities and help them reach their full potential.

Diplopia is a medical term that refers to the condition where a person sees two images of a single object. It is commonly known as double vision. This can occur due to various reasons, such as nerve damage or misalignment of the eyes. Diplopia can be temporary or chronic and can affect one or both eyes. If you're experiencing diplopia, it's essential to consult an eye care professional for proper evaluation and treatment.

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

Conjunctival diseases refer to a group of medical conditions that affect the conjunctiva, which is the thin, clear mucous membrane that covers the inner surface of the eyelids and the white part of the eye (known as the sclera). The conjunctiva helps to keep the eye moist and protected from irritants.

Conjunctival diseases can cause a range of symptoms, including redness, itching, burning, discharge, grittiness, and pain. Some common conjunctival diseases include:

1. Conjunctivitis (pink eye): This is an inflammation or infection of the conjunctiva that can be caused by viruses, bacteria, or allergies. Symptoms may include redness, itching, discharge, and watery eyes.
2. Pinguecula: This is a yellowish, raised bump that forms on the conjunctiva, usually near the corner of the eye. It is caused by an overgrowth of connective tissue and may be related to sun exposure or dry eye.
3. Pterygium: This is a fleshy growth that extends from the conjunctiva onto the cornea (the clear front part of the eye). It can cause redness, irritation, and vision problems if it grows large enough to cover the pupil.
4. Allergic conjunctivitis: This is an inflammation of the conjunctiva caused by an allergic reaction to substances such as pollen, dust mites, or pet dander. Symptoms may include redness, itching, watery eyes, and swelling.
5. Chemical conjunctivitis: This is an irritation or inflammation of the conjunctiva caused by exposure to chemicals such as chlorine, smoke, or fumes. Symptoms may include redness, burning, and tearing.
6. Giant papillary conjunctivitis (GPC): This is a type of allergic reaction that occurs in response to the presence of a foreign body in the eye, such as a contact lens. Symptoms may include itching, mucus discharge, and a gritty feeling in the eye.

Treatment for conjunctival diseases depends on the underlying cause. In some cases, over-the-counter medications or home remedies may be sufficient to relieve symptoms. However, more severe cases may require prescription medication or medical intervention. It is important to consult with a healthcare provider if you experience persistent or worsening symptoms of conjunctival disease.

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

I'm sorry for any confusion, but "reading" is not a term that has a specific medical definition. Reading is the activity or process of deciphering and understanding written words or text. It is a fundamental skill in language acquisition and communication, and is not typically used in a medical context unless there is a concern related to reading difficulties or disorders, such as dyslexia. If you have any questions related to medical terminology or health concerns, I'd be happy to try to help answer those for you!

Uveitis is the inflammation of the uvea, the middle layer of the eye between the retina and the white of the eye (sclera). The uvea consists of the iris, ciliary body, and choroid. Uveitis can cause redness, pain, and vision loss. It can be caused by various systemic diseases, infections, or trauma. Depending on the part of the uvea that's affected, uveitis can be classified as anterior (iritis), intermediate (cyclitis), posterior (choroiditis), or pan-uveitis (affecting all layers). Treatment typically includes corticosteroids and other immunosuppressive drugs to control inflammation.

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

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

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

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

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

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

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

Conjunctivitis is an inflammation or infection of the conjunctiva, a thin, clear membrane that covers the inner surface of the eyelids and the outer surface of the eye. The condition can cause redness, itching, burning, tearing, discomfort, and a gritty feeling in the eyes. It can also result in a discharge that can be clear, yellow, or greenish.

Conjunctivitis can have various causes, including bacterial or viral infections, allergies, irritants (such as smoke, chlorine, or contact lens solutions), and underlying medical conditions (like dry eye or autoimmune disorders). Treatment depends on the cause of the condition but may include antibiotics, antihistamines, anti-inflammatory medications, or warm compresses.

It is essential to maintain good hygiene practices, like washing hands frequently and avoiding touching or rubbing the eyes, to prevent spreading conjunctivitis to others. If you suspect you have conjunctivitis, it's recommended that you consult an eye care professional for a proper diagnosis and treatment plan.

Ocular hypotension is a medical term that refers to a condition where the pressure inside the eye (intraocular pressure or IOP) is lower than normal. The normal range for IOP is typically between 10-21 mmHg (millimeters of mercury). Ocular hypotension can occur due to various reasons, including certain medications, medical conditions, or surgical procedures that affect the eye's ability to produce or drain aqueous humor, the clear fluid inside the eye.

While mild ocular hypotension may not cause any symptoms, more significant cases can lead to complications such as decreased vision, optic nerve damage, and visual field loss. If left untreated, it could potentially result in a condition called glaucoma. It is essential to consult an eye care professional if you suspect ocular hypotension or experience any changes in your vision.

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

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

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

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

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

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

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

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

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

Echothiophate iodide is a cholinesterase inhibitor drug. It works by blocking the breakdown of acetylcholine, a neurotransmitter in the body that is essential for proper nerve function. By preventing the breakdown of acetylcholine, echothiophate iodide can help to improve muscle strength and reduce muscle weakness in individuals with certain neuromuscular disorders.

Echothiophate iodide is used as a diagnostic aid in ophthalmology to test for the presence and severity of glaucoma, as well as to treat certain types of glaucoma by reducing the pressure inside the eye. It is also used off-label to treat myasthenia gravis, a neuromuscular disorder characterized by muscle weakness and fatigue.

The drug is administered via injection or ophthalmic solution, depending on its intended use. Common side effects of echothiophate iodide include blurred vision, eye pain, headache, and nausea. More serious side effects can include seizures, difficulty breathing, and irregular heartbeat.

It is important to note that echothiophate iodide can interact with other medications and should be used with caution in individuals with certain medical conditions. Therefore, it is essential to consult with a healthcare provider before using this medication.

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

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

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

Vision disparity, also known as binocular vision disparity, refers to the difference in the image that is perceived by each eye. This can occur due to a variety of reasons such as misalignment of the eyes (strabismus), unequal refractive power in each eye (anisometropia), or abnormalities in the shape of the eye (astigmatism).

When there is a significant difference in the image that is perceived by each eye, the brain may have difficulty combining the two images into a single, three-dimensional perception. This can result in visual symptoms such as double vision (diplopia), eyestrain, headaches, and difficulty with depth perception.

Vision disparity can be detected through a comprehensive eye examination and may be treated with corrective lenses, prism lenses, vision therapy, or surgery, depending on the underlying cause and severity of the condition.

Pathological nystagmus is an abnormal, involuntary movement of the eyes that can occur in various directions (horizontal, vertical, or rotatory) and can be rhythmical or arrhythmic. It is typically a result of a disturbance in the vestibular system, central nervous system, or ocular motor pathways. Pathological nystagmus can cause visual symptoms such as blurred vision, difficulty with fixation, and oscillopsia (the sensation that one's surroundings are moving). The type, direction, and intensity of the nystagmus may vary depending on the underlying cause, which can include conditions such as brainstem or cerebellar lesions, multiple sclerosis, drug toxicity, inner ear disorders, and congenital abnormalities.

Physiological adaptation refers to the changes or modifications that occur in an organism's biological functions or structures as a result of environmental pressures or changes. These adaptations enable the organism to survive and reproduce more successfully in its environment. They can be short-term, such as the constriction of blood vessels in response to cold temperatures, or long-term, such as the evolution of longer limbs in animals that live in open environments.

In the context of human physiology, examples of physiological adaptation include:

1. Acclimatization: The process by which the body adjusts to changes in environmental conditions, such as altitude or temperature. For example, when a person moves to a high-altitude location, their body may produce more red blood cells to compensate for the lower oxygen levels, leading to improved oxygen delivery to tissues.

2. Exercise adaptation: Regular physical activity can lead to various physiological adaptations, such as increased muscle strength and endurance, enhanced cardiovascular function, and improved insulin sensitivity.

3. Hormonal adaptation: The body can adjust hormone levels in response to changes in the environment or internal conditions. For instance, during prolonged fasting, the body releases stress hormones like cortisol and adrenaline to help maintain energy levels and prevent muscle wasting.

4. Sensory adaptation: Our senses can adapt to different stimuli over time. For example, when we enter a dark room after being in bright sunlight, it takes some time for our eyes to adjust to the new light level. This process is known as dark adaptation.

5. Aging-related adaptations: As we age, various physiological changes occur that help us adapt to the changing environment and maintain homeostasis. These include changes in body composition, immune function, and cognitive abilities.

Distance perception refers to the ability to accurately judge the distance or depth of an object in relation to oneself or other objects. It is a complex process that involves both visual and non-visual cues, such as perspective, size, texture, motion parallax, binocular disparity, and familiarity with the object or scene.

In the visual system, distance perception is primarily mediated by the convergence of the two eyes on an object, which provides information about its depth and location in three-dimensional space. The brain then integrates this information with other sensory inputs and prior knowledge to create a coherent perception of the environment.

Disorders of distance perception can result from various conditions that affect the visual system, such as amblyopia, strabismus, or traumatic brain injury. These disorders can cause difficulties in tasks that require accurate depth perception, such as driving, sports, or manual work.

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

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

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

The postprandial period is the time frame following a meal, during which the body is engaged in the process of digestion, absorption, and assimilation of nutrients. In a medical context, this term generally refers to the few hours after eating when the body is responding to the ingested food, particularly in terms of changes in metabolism and insulin levels.

The postprandial period can be of specific interest in the study and management of conditions such as diabetes, where understanding how the body handles glucose during this time can inform treatment decisions and strategies for maintaining healthy blood sugar levels.

An Oncology Service in a hospital refers to the specialized department or unit that provides comprehensive cancer care and treatment. It is typically staffed with various healthcare professionals such as medical oncologists, radiation oncologists, surgical oncologists, oncology nurses, radiologists, pathologists, social workers, and psychologists who work together to provide a multidisciplinary approach to cancer diagnosis, treatment, and follow-up care.

The oncology service may offer various treatments such as chemotherapy, radiation therapy, immunotherapy, hormone therapy, and surgery, depending on the type and stage of cancer. They also provide supportive care services like pain management, nutritional support, and rehabilitation to help patients manage symptoms and improve their quality of life during and after treatment.

Overall, an Oncology Service in a hospital is dedicated to providing compassionate and evidence-based cancer care to patients and their families throughout the entire cancer journey.

The American Dental Association (ADA) is not a medical condition or diagnosis. It is the largest professional organization of dentists in the United States, with the mission to serve and advance the dental profession, promote oral health, and protect the public. The ADA develops and publishes guidelines and standards for the practice of dentistry, provides continuing education opportunities for dentists, advocates for oral health legislation and policies, and engages in scientific research and evidence-based dentistry.

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

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

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

I'm not aware of a specific medical definition for "ceremonial behavior." However, in general, ceremonial behaviors are actions or rituals that are performed in a formal, ritualistic manner, often as part of a cultural, religious, or social tradition. These behaviors can serve various purposes, such as marking important life events, expressing shared values and beliefs, or reinforcing social bonds.

In some cases, ceremonial behaviors may have health implications. For example, participation in cultural or religious rituals can provide a sense of community and support, which can have positive effects on mental health. Additionally, certain ceremonial practices, such as meditation or prayer, may have direct physiological effects that contribute to stress reduction and relaxation.

However, it's important to note that the term "ceremonial behavior" is not a medical diagnosis or clinical concept, and its meaning can vary depending on the context in which it is used.

Dark adaptation is the process by which the eyes adjust to low levels of light. This process allows the eyes to become more sensitive to light and see better in the dark. It involves the dilation of the pupils, as well as chemical changes in the rods and cones (photoreceptor cells) of the retina. These changes allow the eye to detect even small amounts of light and improve visual acuity in low-light conditions. Dark adaptation typically takes several minutes to occur fully, but can be faster or slower depending on various factors such as age, prior exposure to light, and certain medical conditions. It is an important process for maintaining good vision in a variety of lighting conditions.

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

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

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

"Macaca fascicularis" is the scientific name for the crab-eating macaque, also known as the long-tailed macaque. It's a species of monkey that is native to Southeast Asia. They are called "crab-eating" macaques because they are known to eat crabs and other crustaceans. These monkeys are omnivorous and their diet also includes fruits, seeds, insects, and occasionally smaller vertebrates.

Crab-eating macaques are highly adaptable and can be found in a wide range of habitats, including forests, grasslands, and wetlands. They are also known to live in close proximity to human settlements and are often considered pests due to their tendency to raid crops and steal food from humans.

These monkeys are social animals and live in large groups called troops. They have a complex social structure with a clear hierarchy and dominant males. Crab-eating macaques are also known for their intelligence and problem-solving abilities.

In medical research, crab-eating macaques are often used as animal models due to their close genetic relationship to humans. They are used in studies related to infectious diseases, neuroscience, and reproductive biology, among others.

Separation anxiety is a condition in which an individual experiences excessive and disproportionate fear or distress when separated from a person or place that they are attached to. This condition is commonly diagnosed in children, but it can also affect adults. The anxiety experienced during separation may manifest as excessive worrying, crying, clinginess, panic attacks, or physical symptoms such as nausea, headaches, or rapid heartbeat. In order for a diagnosis of separation anxiety disorder to be made, the symptoms must cause significant distress and impairment in social, occupational, or other areas of functioning.

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

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

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

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

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

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

The gastric fundus is the upper, rounded portion of the stomach that lies above the level of the cardiac orifice and extends up to the left dome-shaped part of the diaphragm. It is the part of the stomach where food and liquids are first stored after entering through the esophagus. The gastric fundus contains parietal cells, which secrete hydrochloric acid, and chief cells, which produce pepsinogen, a precursor to the digestive enzyme pepsin. It is also the site where the hormone ghrelin is produced, which stimulates appetite.

Pilocarpine is a cholinergic agonist, which means it stimulates the parasympathetic nervous system by binding to muscarinic receptors. It is primarily used in the treatment of dry mouth (xerostomia) caused by radiation therapy or Sjögren's syndrome, as well as in the management of glaucoma due to its ability to construct the pupils and reduce intraocular pressure. Pilocarpine can also be used to treat certain cardiovascular conditions and chronic bronchitis. It is available in various forms, including tablets, ophthalmic solutions, and topical gels.

"Papio hamadryas" is a species of old world monkey, also known as the Hamadryas baboon. It is not a medical term or concept. Here's a brief overview of its biological significance:

The Hamadryas baboon (Papio hamadryas) is native to the Horn of Africa and the southwestern Arabian Peninsula. They are highly social primates, living in large groups called troops. These troops can consist of hundreds of individuals, but they are hierarchically structured with multiple adult males, harems of females, and their offspring.

Hamadryas baboons have a distinctive appearance, characterized by their dog-like faces, hairless calluses on their rumps, and long, flowing manes. They primarily feed on plants, but they are also known to consume small vertebrates and invertebrates. Their gestation period is approximately six months, and females typically give birth to a single offspring.

In captivity, Hamadryas baboons have been used as subjects in various biomedical research studies due to their close phylogenetic relationship with humans. However, the term 'Papio hamadryas' itself does not have a medical definition.

Ligaments are bands of dense, fibrous connective tissue that surround joints and provide support, stability, and limits the range of motion. They are made up primarily of collagen fibers arranged in a parallel pattern to withstand tension and stress. Ligaments attach bone to bone, and their function is to prevent excessive movement that could cause injury or dislocation.

There are two main types of ligaments: extracapsular and intracapsular. Extracapsular ligaments are located outside the joint capsule and provide stability to the joint by limiting its range of motion. Intracapsular ligaments, on the other hand, are found inside the joint capsule and help maintain the alignment of the joint surfaces.

Examples of common ligaments in the body include the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) in the knee, the medial collateral ligament (MCL) and lateral collateral ligament (LCL) in the elbow, and the coracoacromial ligament in the shoulder.

Injuries to ligaments can occur due to sudden trauma or overuse, leading to sprains, strains, or tears. These injuries can cause pain, swelling, bruising, and limited mobility, and may require medical treatment such as immobilization, physical therapy, or surgery.

I apologize, but "video recording" is not a term that has a specific medical definition. It generally refers to the process of capturing and storing moving visual images on electronic media, which is used in various medical fields for different purposes such as surgical training, telemedicine consultations, or monitoring patient conditions. However, there is no unique medical meaning associated with this term.

Sign language is not considered a medical term, but it is a visual-manual means of communication used by individuals who are deaf or hard of hearing. It combines hand shapes, orientation, and movement of the hands, arms, or body, along with facial expressions and lip patterns. Different sign languages exist in various countries and communities, such as American Sign Language (ASL) and British Sign Language (BSL).

However, I can provide a definition related to medical terminology that involves the use of gestures for communication purposes:

Gesture (in medical context): A bodily action or movement, often used to convey information or communicate. In some medical situations, healthcare professionals may use simple, predefined gestures to elicit responses from patients who have difficulty with verbal communication due to conditions like aphasia, dysarthria, or being in a coma. These gestures can be part of a more comprehensive system called "gesture-based communication" or "nonverbal communication."

For sign language specifically, you may consult resources related to linguistics, special education, or deaf studies for detailed definitions and descriptions.

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

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

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

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

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

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

Self-help devices, also known as assistive devices or adaptive equipment, are tools that help individuals perform activities of daily living (ADLs) that have become difficult or impossible due to disability, injury, or aging. These devices can help improve a person's independence, safety, and quality of life by reducing the physical demands of daily tasks and compensating for functional limitations.

Examples of self-help devices include:

1. Mobility aids: walkers, canes, crutches, wheelchairs, scooters, and prosthetics that help with mobility and balance.
2. Bathroom aids: raised toilet seats, shower chairs, grab bars, and non-slip mats that help with bathing and toileting.
3. Dressing aids: button hooks, zipper pulls, reachers, and dressing sticks that help with dressing and grooming.
4. Kitchen aids: easy-grip utensils, jar openers, and adapted cutting boards that help with meal preparation and cooking.
5. Communication aids: speech-generating devices, communication boards, and hearing aids that help with communication and social interaction.
6. Cognitive aids: memory aids, calendar organizers, and visual cues that help with memory, attention, and executive functioning.

It is important to consult with healthcare professionals, such as occupational therapists or physical therapists, to determine the appropriate self-help devices for an individual's specific needs and to ensure proper use and safety.

Ophthalmic administration refers to the application or delivery of medications directly into the eye or on the surface of the eye. This route is commonly used for treating various eye conditions such as infections, inflammation, or glaucoma. The medication can be administered in several ways, including:

1. Eye drops: A liquid solution that is instilled into the lower conjunctival sac (the space between the eyeball and the lower eyelid) using a dropper. The patient should be advised to tilt their head back, look up, and pull down the lower eyelid to create a pocket for the drop.
2. Eye ointment: A semi-solid preparation that is applied to the lower conjunctival sac or the edge of the eyelid using a small tube or applicator. Ointments provide a longer contact time with the eye surface compared to eye drops, making them suitable for nighttime use or treating conditions that require prolonged medication exposure.
3. Eye inserts or pellets: Slow-release devices that contain medications and are placed either in the conjunctival sac or on the surface of the eye. These inserts gradually dissolve, releasing the active ingredient over an extended period.
4. Eye patches or bandages: In some cases, medication may be applied to an eye patch or bandage, which is then placed over the affected eye. This method is less common and typically used when other forms of administration are not feasible.

When administering ophthalmic medications, it's essential to follow proper techniques to ensure the correct dosage reaches the target area and minimize systemic absorption. Patients should also be advised about potential side effects, precautions, and storage requirements for their specific medication.

Contrast sensitivity is a measure of the ability to distinguish between an object and its background based on differences in contrast, rather than differences in luminance. Contrast refers to the difference in light intensity between an object and its immediate surroundings. Contrast sensitivity is typically measured using specially designed charts that have patterns of parallel lines with varying widths and contrast levels.

In clinical settings, contrast sensitivity is often assessed as part of a comprehensive visual examination. Poor contrast sensitivity can affect a person's ability to perform tasks such as reading, driving, or distinguishing objects from their background, especially in low-light conditions. Reduced contrast sensitivity is a common symptom of various eye conditions, including cataracts, glaucoma, and age-related macular degeneration.

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

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

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

A tonic pupil, also known as a "Adie's pupil," is a type of abnormal pupillary response named after Sir William John Adie, who first described it in 1932. It is characterized by an initial sluggish or absent reaction to light, followed by a slow and sustained redilation. This condition typically occurs as a result of damage to the ciliary ganglion or short ciliary nerves, which are part of the parasympathetic nervous system.

Tonic pupils can be unilateral (occurring in one eye) or bilateral (occurring in both eyes). They may be associated with other neurological symptoms such as decreased deep tendon reflexes and abnormal sweating patterns, depending on the extent of the damage to the autonomic nervous system.

It is important to note that tonic pupils can also occur as a result of various medical conditions, including viral infections, neurotoxins, trauma, or tumors. Therefore, it is essential to consult with a healthcare professional for proper evaluation and management.

Gastrointestinal motility refers to the coordinated muscular contractions and relaxations that propel food, digestive enzymes, and waste products through the gastrointestinal tract. This process involves the movement of food from the mouth through the esophagus into the stomach, where it is mixed with digestive enzymes and acids to break down food particles.

The contents are then emptied into the small intestine, where nutrients are absorbed, and the remaining waste products are moved into the large intestine for further absorption of water and electrolytes and eventual elimination through the rectum and anus.

Gastrointestinal motility is controlled by a complex interplay between the autonomic nervous system, hormones, and local reflexes. Abnormalities in gastrointestinal motility can lead to various symptoms such as bloating, abdominal pain, nausea, vomiting, diarrhea, or constipation.

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

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

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

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

A truncal vagotomy is a surgical procedure that involves the selective or complete division of the trunks of the vagus nerves. The vagus nerves are pairs of nerves that originate in the brainstem and extend down to the abdomen, providing parasympathetic nerve supply to various organs. In a truncal vagotomy, the vagus nerves are cut above the level of the diaphragm, which results in denervation of the stomach and parts of the digestive tract.

This procedure is typically performed as a treatment for peptic ulcers, as it reduces acid secretion in the stomach by interrupting the nerve supply that stimulates acid production. However, truncal vagotomy can also have side effects such as altered gastric motility and decreased intestinal secretions, which may lead to symptoms like bloating, diarrhea, or dumping syndrome.

It's important to note that there are different types of vagotomy procedures, including selective vagotomy and highly selective vagotomy, which aim to preserve some of the nerve supply to the stomach and minimize side effects. The choice of procedure depends on various factors, such as the location and severity of the ulcer, patient's overall health, and individual preferences.

In medical terms, pressure is defined as the force applied per unit area on an object or body surface. It is often measured in millimeters of mercury (mmHg) in clinical settings. For example, blood pressure is the force exerted by circulating blood on the walls of the arteries and is recorded as two numbers: systolic pressure (when the heart beats and pushes blood out) and diastolic pressure (when the heart rests between beats).

Pressure can also refer to the pressure exerted on a wound or incision to help control bleeding, or the pressure inside the skull or spinal canal. High or low pressure in different body systems can indicate various medical conditions and require appropriate treatment.

Onchocerciasis, Ocular is a medical condition that specifically refers to the eye manifestations caused by the parasitic infection, Onchocerca volvulus. Also known as "river blindness," this disease is spread through the bite of infected blackflies.

Ocular onchocerciasis affects various parts of the eye, including the conjunctiva, cornea, iris, and retina. The infection can cause symptoms such as itching, burning, and redness of the eyes. Over time, it may lead to more serious complications like punctate keratitis (small, scattered opacities on the cornea), cataracts, glaucoma, and ultimately, blindness.

The infection is diagnosed through a skin snip or blood test, which can detect the presence of microfilariae (the larval stage of the parasite) or antibodies against the parasite. Treatment typically involves administering oral medications such as ivermectin, which kills the microfilariae and reduces the risk of eye damage. However, it does not kill the adult worms, so multiple doses are often required to control the infection. In some cases, surgery may be necessary to remove advanced ocular lesions.

Benign mucous membrane pemphigoid (BMMP) is a type of autoimmune blistering disorder that primarily affects the mucous membranes. It is also known as cicatricial pemphigoid or oral pemphigoid. In this condition, the immune system produces antibodies against proteins called BP230 and BP180, which are found in the basement membrane zone of the mucous membranes and skin. This leads to the separation of the epidermis from the dermis, resulting in blisters and erosions.

The term "benign" is used to describe this condition because it typically has a better prognosis compared to other types of pemphigoid, such as bullous pemphigoid or pemphigus vulgaris. However, the term can be misleading as BMMP can still cause significant morbidity and have serious complications, particularly when it affects vital organs like the eyes or respiratory tract.

BMMP commonly involves the mucous membranes of the mouth, nose, throat, genitals, and anus. The skin is less frequently affected, but when it is, the lesions are usually limited to the areas around the eyes, nose, and mouth. The blisters and erosions can cause pain, discomfort, and difficulty with eating, speaking, swallowing, or breathing, depending on the location of the lesions.

The diagnosis of BMMP is typically made based on clinical presentation, histopathology, direct immunofluorescence (DIF), and indirect immunofluorescence (IIF) tests. Treatment usually involves systemic corticosteroids and other immunosuppressive medications to control the blistering and prevent complications. In severe cases, intravenous immunoglobulin or rituximab may be used.

An ophthalmoscope is a medical device used by healthcare professionals to examine the interior structures of the eye, including the retina, optic disc, and vitreous humor. It consists of a handle with a battery-powered light source and a head that contains lenses for focusing. When placed in contact with the patient's dilated pupil, the ophthalmoscope allows the examiner to visualize the internal structures of the eye and assess their health. Ophthalmoscopes are commonly used in routine eye examinations, as well as in the diagnosis and management of various eye conditions and diseases.

Anisocoria is a medical term that refers to an inequality in the size of the pupils in each eye. The pupil is the black, circular opening in the center of the iris (the colored part of the eye) that allows light to enter and strike the retina. Normally, the pupils are equal in size and react similarly when exposed to light or darkness. However, in anisocoria, one pupil is larger or smaller than the other.

Anisocoria can be caused by various factors, including neurological conditions, trauma, eye diseases, or medications that affect the pupillary reflex. In some cases, anisocoria may be a normal variant and not indicative of any underlying medical condition. However, if it is a new finding or associated with other symptoms such as pain, headache, vision changes, or decreased level of consciousness, it should be evaluated by a healthcare professional to determine the cause and appropriate treatment.

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

Obsessive-Compulsive Disorder (OCD) is a mental health disorder characterized by the presence of obsessions and compulsions. Obsessions are recurrent and persistent thoughts, urges, or images that are intrusive, unwanted, and often distressing. Compulsions are repetitive behaviors or mental acts that an individual feels driven to perform in response to an obsession or according to rigid rules, and which are aimed at preventing or reducing anxiety or distress, or preventing some dreaded event or situation. These obsessions and/or compulsions cause significant distress, take up a lot of time (an hour or more a day), and interfere with the individual's daily life, including social activities, relationships, and work or school performance. OCD is considered a type of anxiety disorder and can also co-occur with other mental health conditions.

The lens nucleus, also known as the crystalline lens nucleus, is the central part of the crystalline lens in the eye. The crystalline lens is a biconvex structure located behind the iris and pupil, which helps to refract (bend) light rays and focus them onto the retina.

The lens nucleus is composed of densely packed lens fibers that have lost their nuclei and cytoplasm during differentiation. It is surrounded by the lens cortex, which consists of younger lens fiber cells that are still metabolically active. The lens nucleus is relatively avascular and receives its nutrients through diffusion from the aqueous humor in the anterior chamber of the eye.

The lens nucleus plays an important role in the accommodation process, which allows the eye to focus on objects at different distances. During accommodation, the ciliary muscles contract and release tension on the lens zonules, allowing the lens to become thicker and increase its curvature. This results in a decrease in the focal length of the lens and enables the eye to focus on nearby objects. The lens nucleus is more rigid than the cortex and helps maintain the shape of the lens during accommodation.

Changes in the lens nucleus are associated with several age-related eye conditions, including cataracts and presbyopia. Cataracts occur when the lens becomes cloudy or opaque, leading to a decrease in vision clarity. Presbyopia is a condition that affects the ability to focus on near objects and is caused by a hardening of the lens nucleus and a loss of elasticity in the lens fibers.

Exotropia is a type of ocular misalignment or strabismus, where one eye turns outward (towards the ear) while the other eye remains aligned straight ahead. This condition can be constant or intermittent and may result in limited or absent depth perception, double vision, and in some cases, amblyopia (lazy eye). Exotropia is typically diagnosed during childhood through a comprehensive eye examination by an optometrist or ophthalmologist. Treatment options include eyeglasses, prism lenses, vision therapy, or surgery, depending on the severity and frequency of the misalignment.

The corneal epithelium is the outermost layer of the cornea, which is the clear, dome-shaped surface at the front of the eye. It is a stratified squamous epithelium, consisting of several layers of flat, scale-like cells that are tightly packed together. The corneal epithelium serves as a barrier to protect the eye from microorganisms, dust, and other foreign particles. It also provides a smooth surface for the refraction of light, contributes to the maintenance of corneal transparency, and plays a role in the eye's sensitivity to touch and pain. The corneal epithelium is constantly being renewed through the process of cell division and shedding, with new cells produced by stem cells located at the limbus, the border between the cornea and the conjunctiva.

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

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

Chorioretinitis is a medical term that refers to the inflammation of the choroid and the retina, which are both important structures in the eye. The choroid is a layer of blood vessels that supplies oxygen and nutrients to the retina, while the retina is a light-sensitive tissue that converts light into electrical signals that are sent to the brain and interpreted as visual images.

Chorioretinitis can be caused by various infectious and non-infectious conditions, such as bacterial, viral, fungal, or parasitic infections, autoimmune diseases, or cancer. The symptoms of chorioretinitis may include decreased vision, floaters, blurry vision, sensitivity to light, and eye pain. Treatment for chorioretinitis depends on the underlying cause and may include antibiotics, antiviral medications, corticosteroids, or other immunosuppressive therapies. It is important to seek medical attention promptly if you experience any symptoms of chorioretinitis, as timely diagnosis and treatment can help prevent permanent vision loss.

I'm sorry for any confusion, but "Jurisprudence" is not a term typically used in medical definitions. Jurisprudence refers to the theory and philosophy of law, or the study of legal systems, principles, and practices. It is a subject that falls under the purview of lawyers, judges, and scholars of law. If you have any questions about medical terminology, I'd be happy to help with those!

ISBN 978-81-312-1132-8. Accommodation at Georgia State University Ocular+Accommodation at the U.S. National Library of Medicine ... Three regions make up the accommodation neural circuit, the afferent limb, the efferent limb and the ocular motor neurons that ... The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near ... During the accommodation reflex, the pupil constricts to increase the depth of focus of the eye by blocking the light scattered ...
Aggarwala, K. R.; Kruger, E. S.; Mathews, S; Kruger, P. B. (1995). "Spectral bandwidth and ocular accommodation". Journal of ... Thibos, L. N.; Bradley, A; Still, D. L.; Zhang, X; Howarth, P. A. (1990). "Theory and measurement of ocular chromatic ... Kruger, P. B.; Mathews, S; Aggarwala, K. R.; Sanchez, N (1993). "Chromatic aberration and ocular focus: Fincham revisited". ...
925-939...................................Refraction and errors of refraction and accommodation 939.2-981 ... Ocular therapeutics 110-320...................................Otology. Diseases of the ear 341-437 ...
"Preservatives from the Eye Drops and the Ocular Surface". Romanian Journal of Ophthalmology. 59 (1): 2-5. PMC 5729814. PMID ... A spasm of accommodation (also known as a ciliary spasm, an accommodation, or accommodative spasm) is a condition in which the ... attenuates eye fatigue by improving visual accommodation" For routine cases of spasm of accommodation, the American Optometric ... Normal Amplitude of accommodation Normal Near point of convergence Reduced Negative relative accommodation Difficulty clearing ...
Disorders of ocular muscles, binocular movement, accommodation and refraction). ... Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation. Because of the paralysis of ... van der Hoeve, J.; Flieringa, H. J. (1 March 1924). "Accommodation". British Journal of Ophthalmology. 8 (3): 97-106. doi: ... "Human ocular anatomy". Clinics in Dermatology. 33 (2): 140-146. doi:10.1016/j.clindermatol.2014.10.006. PMID 25704934. ...
Crane, H.D.; Cornsweet, T.N. (1970). "Ocular focus stimulator". Journal of the Optical Society of America. 60 (4): 577. doi: ... Cornsweet, T.N.; Crane, H.D. (1973). "Training the visual accommodation system". Vision Research. 13 (3): 713-715. doi:10.1016/ ...
Medical signs, Disorders of ocular muscles, binocular movement, accommodation and refraction). ...
Two main ocular responses can be distinguished - vergence of eyes and accommodation. Both of these mechanisms are crucial in ... The vergence-accommodation conflict is caused due to factors in human physiology like the accommodation reflex. VAC occurs when ... Vergence-accommodation conflict (VAC), also known as accommodation-vergence conflict, is a visual phenomenon that occurs when ... Accommodation is the eye's focusing mechanism and it is engaged to produce a sharp image on a retina. Both of these mechanisms ...
oph/723 at eMedicine-"Presbyopia: Cause and Treatment" Ocular+Accommodation at the U.S. National Library of Medicine Medical ... Excessive accommodation and spasm of accommodation are types of increased accommodation.[citation needed] Presbyopia, ... It can be broadly classified into two, decreased accommodation and increased accommodation. Decreased accommodation may occur ... Accommodation usually acts like a reflex, including part of the accommodation-vergence reflex, but it can also be consciously ...
... is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type ... accommodation and refraction). ...
To control accommodation with a fixation target ensure it is maintained by asking the patient to identify the next letter. ... doi:10.1016/j.ajo.2007.09.012 Campos, E.C., & von Noorden, G.K. (2006). Binocular vision and ocular motility (6th ed.) (p.177) ... The prism cover test (PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment ... Ansons, A. M., & Davis, H. (2014). Diagnosis and Management of Ocular Motility Disorders (4th ed.). pp. 97. London: Blackwell. ...
Articles with short description, Short description matches Wikidata, Disorders of ocular muscles, binocular movement, ... accommodation and refraction, Syndromes). ... There have been cases of improvement in extra-ocular movement ...
Articles with short description, Short description is different from Wikidata, Disorders of ocular muscles, binocular movement ... accommodation and refraction). ...
People may complain of neck pain, after years of chronic head tilting (ocular torticollis), but this is also encountered in ... accommodation and refraction). ... ocular torticollis) from an early age. Most people with ... Boricean ID, Bărar A (2011). "Understanding ocular torticollis in children". Oftalmologia. 55 (1): 10-26. PMID 21774381. Joel S ... Articles with short description, Short description is different from Wikidata, Disorders of ocular muscles, binocular movement ...
Articles with short description, Short description is different from Wikidata, Disorders of ocular muscles, binocular movement ... accommodation and refraction). ...
... refraction Accommodative system Amplitude of accommodation Negative relative accommodation Positive relative accommodation ... Ocular motility should always be tested, especially when patients complain of double vision or physicians suspect neurologic ... Close inspection of the anterior eye structures and ocular adnexa are often done with a slit lamp which is a table mounted ... If there is a small, irregular pupil that constricts poorly to light, but normally to accommodation, this is an Argyll ...
Articles with short description, Short description matches Wikidata, Disorders of ocular muscles, binocular movement, ... accommodation and refraction, Vision, Animal diseases). ...
Articles with short description, Short description is different from Wikidata, Disorders of ocular muscles, binocular movement ... accommodation and refraction, Oculomotor nerve). ...
Disorders of ocular muscles, binocular movement, accommodation and refraction). ... also known as excessive accommodation or accommodation excess) occurs when an individual uses more than normal accommodation ( ... It may occur due to excessive accommodation or spasm of accommodation. Parinaud's syndrome, which can mimic some aspects of ... Modern definitions simply regard it as an inability to relax accommodation readily. Excessive accommodation is seen in ...
Disorders of ocular muscles, binocular movement, accommodation and refraction, Syndromes). ...
There have been reports of disturbances in ocular accommodation occurring after the concomitant use of the related drug ...
Disorders of ocular muscles, binocular movement, accommodation and refraction). ... However, where the degree of error is small enough to allow the child to generate clear vision by over-accommodation, but large ... These problems may directly affect the extra-ocular muscles themselves, and may also result from conditions affecting the nerve ... The over-convergence associated with the extra accommodation required to overcome a hyperopic refractive error can precipitate ...
When the details of the examination and history indicate a familial history of similar ocular or systemic disease, whether or ... Often treatment is relegated to lifestyle alterations and accommodations and supportive measures.[citation needed] Those ... diseases understood as congenital in origin could either be specific to the ocular organ system (LHON, DOA) or syndromic (MELAS ...
Disorders of ocular muscles, binocular movement, accommodation and refraction). ... It is caused by both genetic and environmental factors, such as mechanical stretching, excessive eye work and accommodation, as ...
He is probably best known for his theory regarding the mechanism of accommodation, of which he disagreed with the accommodation ... He conducted research of entoptic phenomenon, Purkinje images, the etiology of myopia, and Listing's law of ocular movement. He ... Accommodation, Paris 1909 Octave Doin, ("Hermann von Helmholtz and the Theory of Accommodation") which was critical to ... Furthermore, he stated that during accommodation, while the central part of the anterior surface of the lens is bulged, the ...
... reduced accommodation abilities, and headaches. Visual outcomes for patients with ocular trauma due to blast injuries vary, and ... Ocular injury reduction from ocular protection use in current combat operations. J Trauma. 2009. 66(4):S99-S103. (Articles with ... However, ocular trauma most commonly falls under the realm of secondary blast injuries, in which debris displaced by the blast ... Ocular trauma may result from primary blast exposure. Spallation forces arise as the blast wave displaces a dense medium across ...
... through eye strain or fatigue of ocular systems. It is common in young adults who have active accommodation, and classically ... Organic causes may include systemic or ocular medications, brain stem injury, or active ocular inflammation such as uveitis. ... "Acute Adult Onset Comitant Esotropia Associated with Accommodative Spasm". Chan R, Trobe J (2002). "Spasm of accommodation ... "Comparative analysis of the efficacy of some methods of conservative treatment of accommodation spasms and myopia in children ...
Further, the ocular lens yellows with age, providing added protection. However, the lens also becomes more rigid with age, ... losing most of its accommodation-the ability to change shape to focus from far to near-a detriment due probably to protein ... Ocular albinism affects not only eye pigmentation but visual acuity, as well. People with albinism typically test poorly, ... A decreased molecular weight or a decrease in the degree of polymerization of ocular melanin has been proposed to turn the ...
Disorders of ocular muscles, binocular movement, accommodation and refraction, Visual disturbances and blindness, Vision). ...
Book on eye diseases, therapeutics and ocular surgery. Ein neues Ophthalmotrop, 1857 - A new ophthalmotrope. Das Stereoscop : ... Pagel: Biographical Dictionary excellent doctors of the nineteenth century (biography) [1] On the anomalies of accommodation ...
ISBN 978-81-312-1132-8. Accommodation at Georgia State University Ocular+Accommodation at the U.S. National Library of Medicine ... Three regions make up the accommodation neural circuit, the afferent limb, the efferent limb and the ocular motor neurons that ... The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near ... During the accommodation reflex, the pupil constricts to increase the depth of focus of the eye by blocking the light scattered ...
Ocular. Common (1% to 10%): Vision abnormalities, accommodation abnormalities, diplopia, Frequency not reported: Blurred vision ...
Difficulties in visual accommodation, Mydriasis, Visual disturbance. Dry eye$, Ocular hypertension. Cardiac disorders* ... Methylphenidate can cause dizziness, drowsiness and visual disturbances including difficulties with accommodation, diplopia, ...
Ocular dominance and patient satisfaction after monovision induced by intraocular lens implantation. J Cataract Refract Surg. ... Helmholtz Theory of Accommodation. The Helmholtz theory of accommodation is based on the concept that the crystalline lens ... He demonstrated that accommodation did not occur in aphakes. He realized that accommodation had to result from a change in ... In 1864, Donders studied the change of the amplitude of accommodation with age. He found that the amplitude of accommodation ...
All had normal acuity and no ocular pathology. Participants completed a questionnaire regarding their reading habits and ... including accommodation. ...
Neural control of ocular accommodation. 10:00 - 10:30 am Laura Thomas, North Dakota State University. Visual biases in peri- ...
... disorders of refraction and accommodation ranked 18th in terms of the numbers of outpatient encounters and 7th in the numbers ... 1 was an ocular injury (superficial ocular injuries); 1 was a glaucoma and related condition (preglaucoma and ocular ... Ocular injuries accounted for 4.9% of total medical encounters and 13.3% of total hospital bed days. Out of the total ocular ... for ocular and vision-related conditions. For summary purposes, ocular and vision-specific diagnoses (as defined by the ICD-10 ...
Ocular/Ophthalmic Systemic poisoning typically causes pinpoint pupils and spasm of the muscle of visual accommodation (i.e., ...
Disorders of ocular muscles, binocular movement, accommodation and refraction Visual disturbances and blindness Other disorders ...
... is an entity encompassing visual and ocular symptoms arising due to the prolonged use of digital electronic devices. It is ... Accommodation or vergence-related symptoms are secondary to excessive work and related to anomalies of accommodation or ... Eyeblink helps maintain a normal ocular surface through a whole cycle of secretion of tears, wetting of ocular surface, ... Blue Light Exposure: Ocular Hazards and Prevention-A Narrative Review Article Open access 18 February 2023 ...
... accommodations and modifications may be necessary in addition to remediation.2,4 Examples of accommodations include extra time ... Visual-ocular control of normal and learning-disabled children. Dev Med Child Neurol. ... Convergence and accommodation are also required for handheld games. Thus, if visual deficits were a major cause of reading ... With proper remediation, accommodations, and support, children with dyslexia and learning disabilities can succeed. ...
Infants control of their visual experience through vergence and accommodation. T. Rowan Candy1; 1University of Indiana ... the role of the ocular motor visual system in defining retinal visual experience during infancy and early childhood has been ... This work offers the possibility of understanding the early development of strabismus where accommodation-vergence synergy ... vergence eye movements and accommodation, showing that these responses are coupled, associated with sensitivity to binocular ...
... which results in fatigue to both the ocular muscles that are responsible for visual accommodation and muscles involved in eye ... This fatigue causes blurriness and/or double vision, and is not something the ocular muscles learn to compensate for; therefore ... Key Point: CVS causes temporary symptoms of pain and discomfort to both ocular and skeletal muscles that subside after ending ... With computers becoming ubiquitous there is an increase in prevalence for an associated ocular disorder called Computer Vision ...
Tropicamide is an anticholinergic drug used to dilate the pupil of the eye for ocular examination and procedures. Read more ... It is widely used to dilate the pupil of the eye for ocular examination and various ocular procedures. Tropicamide acts by ... This leads to pupil dilation and paralysis of the eye accommodation. The cycloplegic effect of tropicamide has enabled its use ... It is used before various eye examinations and ocular procedures to widen the pupil and aid in better examination. Consult our ...
Topical ivermectin 1.0% cream in the treatment of ocular demodicosis. Smith, M., Wolffsohn, J. S. & Chiang, J. C. B., 3 Dec ... Three-dimensional magnetic resonance imaging of the phakic crystalline lens during accommodation. Sheppard, A., Evans, C. J., ...
Ocular manifestations may be the manifesting features of botulism. However, their absence does not exclude this disease, since ... Accommodation paresis, with blurred vision * Pupil dysfunction with mydriasis and poorly reactive pupils ... the seven different toxins appear to involve the ocular system to various degrees. ...
Accommodation and extraocular movements should be tested. Ocular structures are inspected by using a slit lamp or other ... Other ocular symptoms are evaluated by eye examination as clinically indicated. An old photograph of the patient or the ... or third cranial nerve palsy Third Cranial (Oculomotor) Nerve Disorders Third cranial nerve disorders can impair ocular ... or third cranial nerve palsy Third Cranial (Oculomotor) Nerve Disorders Third cranial nerve disorders can impair ocular ...
Around half of ocular melanomas are class 1, which carry a low risk of metastasis. The other half are class 2, which have a ... intervenes in alteration of the shape of the crystalline lens during accommodation, and secretes hyaluronic acid into the ... The ocular tissue where these tumors arise, the uvea, is a densely pigmented layer that lies for the most part between the ... The incidence of ocular melanoma among Blacks is extremely rare. Hispanics and Asians are thought to have an intermediate risk ...
Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.. Multigene Family. A set of genes descended by duplication ...
H49-H52 - Disorders of ocular muscles, binocular movement, accommodation and refraction Close. ...
Additionally, decreased or transient loss of accommodation may occur during pregnancy or within the postpartum period. ... In up to one third of cases, ocular sequelae have been reported. The most common ocular complaint is visual blurriness; however ... Physiologic Ocular Changes Occurring During Pregnancy. Cornea. Corneal sensitivity has been found to be decreased in most ... Pathologic Ocular Changes During Pregnancy. Pregnancy-induced hypertension (preeclampsia). The onset of hypertension (,140/90 ...
Ocular movements were good in all directions. Hirschberg test without spectacles showed left esotropia 300 and with spectacles ... The uncorrected hypermetropic refractive abnormality can cause excessive accommodation to focus the image on the retina so that ... The goal of surgery is not to make the patient spectacles-free but to obtain ocular alignment and improve binocular vision ... Esodeviation is the most common form of strabismus in children, around 50 % of the ocular deviation in the pediatric population ...
DISCUSSION: Ocular dysfunction that commonly occurs with concussion includes abnormalities of accommodation, convergence, ... On examination of ocular movements, there was -6 limitation of adduction. There was no limitation in other ocular movements. In ... Pre- and post-operative measurements consisted of visual acuity, cycloplegic refraction, ocular alignment, ocular motility, ... BACKGROUND: Ocular dysfunction, including eye movement defects, has been documented in up to 69% of patients with concussion. ...
Accommodation. Accommodation is the process by which the vertebrate eye adjusts focus on an object as it moves closer or ... In a similar manner, fish have a vestibulo-ocular reflex which stabilizes visual images on the retina when it moves its tail. ... Humans have a vestibulo-ocular reflex, which is a reflex eye movement that stabilizes images on the retina during head movement ... Whereas birds and mammals achieve accommodation by deforming the lens of their eyes, fish and amphibians normally adjust focus ...
12) External performance test on ocular accommodation comparing spherical ZEISS Single Vision Lenses to ZEISS SmartLife Digital ...
School-aged children with developmental dyslexia (DD) exhibit more vergence, accommodation and ocular motor tracking deficits ... accommodation deficits and impaired ocular tracking were 47%, 46% and 19%, respectively.1 ...
Is Astaxanthin Antioxidant & Ocular Support Formula suitable for use by both men and women? Yes. Astaxanthin is beneficial for ... In addition to its effects on general health, astaxanthin promotes healthy visual accommodation and retinal capillary blood ... Prime Astaxanthin Antioxidant & Ocular Support Formula is made exclusively in a 6 mg serving, which is superior for promoting ... This product is also great for people who want healthy ocular health (vision). Why is this product placed in the Prime product ...
  • Third Cranial (Oculomotor) Nerve Disorders Third cranial nerve disorders can impair ocular motility, pupillary function, or both. (msdmanuals.com)
  • Digital eye strain (DES) is an entity encompassing visual and ocular symptoms arising due to the prolonged use of digital electronic devices. (springer.com)
  • Non-ocular symptoms associated with eye strain include stiff neck, general fatigue, headache, and backache. (springer.com)
  • DES symptoms can be broadly divided into ocular surface-related symptoms like irritation/burning eyes, dry eyes, eyestrain, headache, tired eyes, sensitivity to bright lights, and eye discomfort. (springer.com)
  • Accommodation-related symptoms include blurred near or distance vision after computer use and difficulty refocusing from one distance to another. (springer.com)
  • Key Point: CVS causes temporary symptoms of pain and discomfort to both ocular and skeletal muscles that subside after ending computer use, but resume once computer use begins again. (cdc.gov)
  • Other ocular symptoms are evaluated by eye examination as clinically indicated. (msdmanuals.com)
  • The Helmholtz theory of accommodation is based on the concept that the crystalline lens changes in shape with relaxation of zonular fibers. (medscape.com)
  • In 1801, Thomas Young, using ingenious experiments, provided evidence that accommodation results from changes in shape of the crystalline lens. (medscape.com)
  • He realized that accommodation had to result from a change in position or shape of the crystalline lens. (medscape.com)
  • He concluded that accommodation results from a change in shape of the crystalline lens. (medscape.com)
  • [ 13 ] In 1849, Langenbeck was able to observe in a patient that the Purkinje image from the anterior surface of the crystalline lens became smaller during accommodation by using a candle and a magnifying glass. (medscape.com)
  • He correctly concluded that the anterior surface of the crystalline lens becomes more convex during accommodation. (medscape.com)
  • However, the majority of investigations have concluded that despite changes in size, shape, and refractive index distribution, the focal characteristics of the crystalline lens remain constant during ocular development in humans and chicks. (arvojournals.org)
  • it produces aqueous humor, facilitates trabecular outflow, intervenes in alteration of the shape of the crystalline lens during accommodation, and secretes hyaluronic acid into the vitreous. (medscape.com)
  • Consult our medical experts for the best treatment for ocular disorders. (yashodahospitals.com)
  • Past medical history includes known ocular disorders and surgeries and exposure to medications. (msdmanuals.com)
  • It is widely used to dilate the pupil of the eye for ocular examination and various ocular procedures. (yashodahospitals.com)
  • Tropicamide is also used in various ocular producers to dilate the pupil for ease of the procedure. (yashodahospitals.com)
  • All had normal acuity and no ocular pathology. (ski.org)
  • Separation and disruption of the overlying ciliary epithelium decreases its production of aqueous humor with consequent ocular hypotension. (medscape.com)
  • This lens is engineered to mimic the aqueous layer of the ocular surface of the eye, with a water content that is 33% at the core and approaches 100% at the outer surface. (medscape.com)
  • The peristriate area 19 interprets accommodation, and sends signals via the Edinger-Westphal nucleus and the 3rd cranial nerve to the ciliary muscle, the medial rectus muscle and (via parasympathetic fibres) the sphincter pupillae muscle. (wikipedia.org)
  • The ciliary muscles are responsible for the lens accommodation response. (wikipedia.org)
  • There are various theories on how ciliary muscle contraction alters zonular tension to increase the optical power of the lens during accommodation. (medscape.com)
  • The mechanism involved, is a relaxation of the ciliary muscle, since it will not have to stress anymore to perform accommodation for near focus work, as it did, when the patient was wearing minus lenses (allowing for far vision). (whale.to)
  • Another interesting work was done by R.F. Fisher, who calculated The force of contraction of the human ciliary muscle during accommodation (in newton, N) for a given amount of dioptres. (whale.to)
  • The cycloplegic effect of tropicamide has enabled its use in various eye examinations and ocular procedures to achieve required dilation. (yashodahospitals.com)
  • Ocular manifestations may be the manifesting features of botulism. (medscape.com)
  • According to Dr. Prentice in his book, The Eye in its Relation to Health (and here ), myopia is caused by abnormal nerve innervations and imbalances in the ocular muscles due to excessive nearwork. (whale.to)
  • CVS is caused by long periods of computer use, which results in fatigue to both the ocular muscles that are responsible for visual accommodation and muscles involved in eye movement. (cdc.gov)
  • we hypothesized that sustained (≥20 minutes) reading would induce fatigue, affecting oculomotor performance, including accommodation. (ski.org)
  • Three regions make up the accommodation neural circuit, the afferent limb, the efferent limb and the ocular motor neurons that are between the afferent and efferent limb. (wikipedia.org)
  • Proximal cues appear more influential in early convergence and accommodation than the binocular disparity cues that become the major drive in older children and adults. (reading.ac.uk)
  • The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near object, then looking at a distant object (and vice versa), comprising coordinated changes in vergence, lens shape (accommodation) and pupil size. (wikipedia.org)
  • Our laboratory has used surveys, remote haploscopic photorefraction and clinical tests to study the development of ocular alignment, convergence, accommodation and their linkages in typical and atypical infants. (reading.ac.uk)
  • 18. Horwood A, Riddell P. The use of cues to convergence and accommodation in naïve, uninstructed participants. (reading.ac.uk)
  • Abnormality of the accommodative convergence to accommodation ratio may cause certain types of strabismus . (medscape.com)
  • This study provides evidence that the refractive development of the chick lens is not independent of the refractive development of the ocular globe and that chick lenticular development is influenced by both genetics and visual experience. (arvojournals.org)
  • Some investigators believe that the lens contributes significantly to normal ocular development, particularly to isometropia, the condition of equal refractive state for both eyes. (arvojournals.org)
  • Early instability of ocular alignment and accommodation usually resolves by 8-9 weeks of age. (reading.ac.uk)
  • 5. Horwood A. Maternal observations of ocular alignment in infants. (reading.ac.uk)
  • 14. Horwood A, Riddell P. Developmental changes in the balance of disparity, blur and looming/proximity cues to drive ocular alignment and focus. (reading.ac.uk)
  • When the SEOM is difficult to resect, a personalized surgical strategy may be required to achieve a good ocular alignment. (bvsalud.org)
  • Optic nerve conditions and visual discomfort/disturbances accounted for more than one-quarter (30.1%) of all ocular and vision-related hospital bed days. (health.mil)
  • Ocular structures are inspected by using a slit lamp or other magnification to identify structural abnormalities and ptosis. (msdmanuals.com)
  • The 3 specific ocular and vision-related conditions that accounted for the most medical encounters (i.e., myopia, astigmatism, and acute conjunctivitis) accounted for almost one-half (47.7%) of all ocular and vision-related medical encounters overall. (health.mil)
  • New-onset myopia and increased progression of existing myopia became one of the most significant ocular health complications. (springer.com)
  • Financial costs of ocular injuries and visual dysfunction resulting from traumatic brain injury have been recently reported and are significant. (health.mil)
  • The bank has made financial accommodations for customers affected by the pandemic. (adjectives-for.com)
  • We describe a four-year-old girl with bilateral severe iris hypoplasia and secondary ocular hypertension. (bvsalud.org)
  • It is used before various eye examinations and ocular procedures to widen the pupil and aid in better examination. (yashodahospitals.com)
  • During the accommodation reflex, the pupil constricts to increase the depth of focus of the eye by blocking the light scattered by the periphery of the cornea. (wikipedia.org)
  • This leads to pupil dilation and paralysis of the eye accommodation. (yashodahospitals.com)
  • This work offers the possibility of understanding the early development of strabismus where accommodation-vergence synergy develops atypically. (visionsciences.org)
  • this category accounted for slightly more than one-half (51.1%) of all ocular and vision-related medical encounters. (health.mil)
  • As outlined by the American Optometric association, digital eye strain encompasses a cluster of ocular and vision-related problems attributed to prolonged usage of desktops, laptops, mobile phones, tablets, e-readers, and storage devices [ 1 ]. (springer.com)
  • Relative accommodation allows us to shift our focus from near to far objects effortlessly. (adjectives-for.com)
  • Whether it's reasonable accommodation that bespeaks affordability, or temporary accommodation hinting at short-term stays, each adjective unfolds a story. (adjectives-for.com)
  • I'm afraid we don't have any temporary accommodation available at the moment. (adjectives-for.com)
  • The term accommodation refers to a temporary solution for a problem. (adjectives-for.com)
  • He demonstrated that accommodation did not occur in aphakes. (medscape.com)
  • Additionally, decreased or transient loss of accommodation may occur during pregnancy or within the postpartum period. (medscape.com)
  • I am inspired a.o. by the work of eye surgeons Dr. Prentice (USA) and Dr. Hollwich (Germany), who documented the profound influence of ocular light on the human organism. (whale.to)
  • All the Eye media involved in the central ocular light pathways (focused, foveal vision) are connected to the sympathetic division of the Autonomic Nervous System (ANS) and accompanies accommodation for far vision . (whale.to)
  • The nuances these adjectives bring to light are crucial for understanding the multifaceted nature of accommodations. (adjectives-for.com)
  • In up to one third of cases, ocular sequelae have been reported. (medscape.com)
  • The term suitable accommodation emphasizes the fit for specific needs, and public accommodation opens up discussions about accessibility and inclusivity. (adjectives-for.com)
  • Adequate housing includes secure accommodation and security of tenure. (adjectives-for.com)
  • Type 508 Accommodation and the title of the report in the subject line of e-mail. (cdc.gov)
  • Effective prioritization of the magnitude and burden of ocular and visual conditions is essential to inform the targets for prevention, allocation of resources, training objectives, and research goals. (health.mil)
  • Their mutual accommodation was essential to a continued working relationship. (adjectives-for.com)
  • The resort offers luxurious accommodation with stunning ocean views and private balconies. (adjectives-for.com)
  • We regret that we are unable to offer further accommodation at this time. (adjectives-for.com)
  • The hotel boasts excellent accommodation with spacious rooms and luxurious amenities. (adjectives-for.com)
  • With computers becoming ubiquitous there is an increase in prevalence for an associated ocular disorder called Computer Vision Syndrome (CVS). (cdc.gov)
  • In 1619, Scheiner, a Jesuit priest, proved that accommodation resulted from a change in the optical power of the eye and that the eye obeyed the laws of optics. (medscape.com)
  • This process, called accommodation, is due to a change in shape of the lens. (medscape.com)