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.
A series of tests used to assess various functions of the eyes.
Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132).
The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.
The selecting and organizing of visual stimuli based on the individual's past experience.
A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications.
Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.
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 removal of a cataractous CRYSTALLINE LENS from the eye.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. Low vision generally refers to visual disorders that are caused by diseases that cannot be corrected by refraction (e.g., MACULAR DEGENERATION; RETINITIS PIGMENTOSA; DIABETIC RETINOPATHY, etc.).
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)
Removal of the whole or part of the vitreous body in treating endophthalmitis, diabetic retinopathy, retinal detachment, intraocular foreign bodies, and some types of glaucoma.
Fluid accumulation in the outer layer of the MACULA LUTEA that results from intraocular or systemic insults. It may develop in a diffuse pattern where the macula appears thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with various underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, DIABETIC RETINOPATHY, and posterior segment inflammatory disease. (From Survey of Ophthalmology 2004; 49(5) 470-90)
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.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
Application of tests and examinations to identify visual defects or vision disorders occurring in specific populations, as in school children, the elderly, etc. It is differentiated from VISION TESTS, which are given to evaluate/measure individual visual performance not related to a specific population.
The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.
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.
Refraction of LIGHT effected by the media of the EYE.
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)
Persons with loss of vision such that there is an impact on activities of daily living.
An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)
Method of measuring and mapping the scope of vision, from central to peripheral of each eye.
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)
Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.
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)
Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.
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)
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.
Damage or trauma inflicted to the eye by external means. The concept includes both surface injuries and intraocular injuries.
Separation of the inner layers of the retina (neural retina) from the pigment epithelium. Retinal detachment occurs more commonly in men than in women, in eyes with degenerative myopia, in aging and in aphakia. It may occur after an uncomplicated cataract extraction, but it is seen more often if vitreous humor has been lost during surgery. (Dorland, 27th ed; Newell, Ophthalmology: Principles and Concepts, 7th ed, p310-12).
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Diseases affecting the eye.
The administration of substances into the VITREOUS BODY of the eye with a hypodermic syringe.
The use of green light-producing LASERS to stop bleeding. The green light is selectively absorbed by HEMOGLOBIN, thus triggering BLOOD COAGULATION.
The blending of separate images seen by each eye into one composite image.
A condition of an inequality of refractive power of the two eyes.
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 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)
The absence or restriction of the usual external sensory stimuli to which the individual responds.
Artificial implanted lenses.
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.
Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.
Recording of electric potentials in the retina after stimulation by light.
Relatively bright light, or the dazzling sensation of relatively bright light, which produces unpleasantness or discomfort, or which interferes with optimal VISION, OCULAR. (Cline et al., Dictionary of Visual Science, 4th ed)
A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)
A membrane on the vitreal surface of the retina resulting from the proliferation of one or more of three retinal elements: (1) fibrous astrocytes; (2) fibrocytes; and (3) retinal pigment epithelial cells. Localized epiretinal membranes may occur at the posterior pole of the eye without clinical signs or may cause marked loss of vision as a result of covering, distorting, or detaching the fovea centralis. Epiretinal membranes may cause vascular leakage and secondary retinal edema. In younger individuals some membranes appear to be developmental in origin and occur in otherwise normal eyes. The majority occur in association with retinal holes, ocular concussions, retinal inflammation, or after ocular surgery. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p291)
Perforations through the whole thickness of the retina including the macula as the result of inflammation, trauma, degeneration, etc. The concept includes retinal breaks, tears, dialyses, and holes.
Deeply perforating or puncturing type intraocular injuries.
The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.
The transparent, 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.
Images seen by one eye.
Blockage of the RETINAL VEIN. Those at high risk for this condition include patients with HYPERTENSION; DIABETES MELLITUS; ATHEROSCLEROSIS; and other CARDIOVASCULAR DISEASES.
The minimum amount of stimulus energy necessary to elicit a sensory response.
A pathological process consisting of the formation of new blood vessels in the CHOROID.
Nystagmus present at birth or caused by lesions sustained in utero or at the time of birth. It is usually pendular, and is associated with ALBINISM and conditions characterized by early loss of central vision. Inheritance patterns may be X-linked, autosomal dominant, or recessive. (Adams et al., Principles of Neurology, 6th ed, p275)
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)
Diseases of the cornea.
A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of EYE DISEASES (e.g., RETINAL DISEASES and GLAUCOMA); OPTIC NERVE DISEASES, and other conditions.
An esterified form of TRIAMCINOLONE. It is an anti-inflammatory glucocorticoid used topically in the treatment of various skin disorders. Intralesional, intramuscular, and intra-articular injections are also administered under certain conditions.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)
Defects of color vision are mainly hereditary traits but can be secondary to acquired or developmental abnormalities in the CONES (RETINA). Severity of hereditary defects of color vision depends on the degree of mutation of the ROD OPSINS genes (on X CHROMOSOME and CHROMOSOME 3) that code the photopigments for red, green and blue.
Partial or total replacement of all layers of a central portion of the cornea.
A surgical procedure to correct MYOPIA by CORNEAL STROMA subtraction. It involves the use of a microkeratome to make a lamellar dissection of the CORNEA creating a flap with intact CORNEAL EPITHELIUM. After the flap is lifted, the underlying midstroma is reshaped with an EXCIMER LASER and the flap is returned to its original position.
Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.
Surgery performed on the eye or any of its parts.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
The aperture in the iris through which light passes.
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)
Agents that dilate the pupil. They may be either sympathomimetics or parasympatholytics.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.
Gas lasers with excited dimers (i.e., excimers) as the active medium. The most commonly used are rare gas monohalides (e.g., argon fluoride, xenon chloride). Their principal emission wavelengths are in the ultraviolet range and depend on the monohalide used (e.g., 193 nm for ArF, 308 nm for Xe Cl). These lasers are operated in pulsed and Q-switched modes and used in photoablative decomposition involving actual removal of tissue. (UMDNS, 2005)
Examination of the interior of the eye with an ophthalmoscope.
Hemorrhage into the VITREOUS BODY.
Voluntary or reflex-controlled movements of the eye.
A refractive error in which rays of light entering the eye parallel to the optic axis are brought to a focus behind the retina, as a result of the eyeball being too short from front to back. It is also called farsightedness because the near point is more distant than it is in emmetropia with an equal amplitude of accommodation. (Dorland, 27th ed)
The normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.
The awareness of the spatial properties of objects; includes physical space.
Perception of three-dimensionality.
A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.
The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.
The administration of substances into the eye with a hypodermic syringe.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Normal nystagmus produced by looking at objects moving across the field of vision.
An operation for retinal detachment which reduces the size of the globe by indenting the sclera so that it approximates the retina.
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.
Disorder occurring in the central or peripheral area of the cornea. The usual degree of transparency becomes relatively opaque.
Suppurative inflammation of the tissues of the internal structures of the eye frequently associated with an infection.
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.
Presence of an intraocular lens after cataract extraction.
Atrophy of the optic disk which may be congenital or acquired. This condition indicates a deficiency in the number of nerve fibers which arise in the RETINA and converge to form the OPTIC DISK; OPTIC NERVE; OPTIC CHIASM; and optic tracts. GLAUCOMA; ISCHEMIA; inflammation, a chronic elevation of intracranial pressure, toxins, optic nerve compression, and inherited conditions (see OPTIC ATROPHIES, HEREDITARY) are relatively common causes of this condition.
Bleeding from the vessels of the retina.
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)
Introduction of substances into the body using a needle and syringe.
Asymmetries in the topography and refractive index of the corneal surface that affect visual acuity.
A surgical procedure or KERATOPLASTY involving selective stripping and replacement of diseased host DESCEMET MEMBRANE and CORNEAL ENDOTHELIUM with a suitable and healthy donor posterior lamella. The advantage to this procedure is that the normal corneal surface of the recipient is retained, thereby avoiding corneal surface incisions and sutures.
A form of RETINAL DEGENERATION in which abnormal CHOROIDAL NEOVASCULARIZATION occurs under the RETINA and MACULA LUTEA, causing bleeding and leaking of fluid. This leads to bulging and or lifting of the macula and the distortion or destruction of central vision.
The sensory discrimination of a pattern shape or outline.
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.
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 real or apparent movement of objects through the visual field.
Disorders of the choroid including hereditary choroidal diseases, neoplasms, and other abnormalities of the vascular layer of the uvea.
The inner portion of a retinal rod or a cone photoreceptor cell, situated between the PHOTORECEPTOR CONNECTING CILIUM and the synapse with the adjacent neurons (RETINAL BIPOLAR CELLS; RETINAL HORIZONTAL CELLS). The inner segment contains the cell body, the nucleus, the mitochondria, and apparatus for protein synthesis.
Inflammation of the optic nerve. Commonly associated conditions include autoimmune disorders such as MULTIPLE SCLEROSIS, infections, and granulomatous diseases. Clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (Marcus-Gunn pupil), and in some instances optic disc hyperemia and swelling. Inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis).
The pressure of the fluids in the eye.
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)
Sudden ISCHEMIA in the RETINA due to blocked blood flow through the CENTRAL RETINAL ARTERY or its branches leading to sudden complete or partial loss of vision, respectively, in the eye.
The light sensitive outer portion of a retinal rod or a cone photoreceptor cell. The outer segment contains a stack of disk membranes laden with photoreceptive pigments (RETINAL PIGMENTS). The outer segment is connected to the inner segment by a PHOTORECEPTOR CONNECTING CILIUM.
The period following a surgical operation.
The coagulation of tissue by an intense beam of light, including laser (LASER COAGULATION). In the eye it is used in the treatment of retinal detachments, retinal holes, aneurysms, hemorrhages, and malignant and benign neoplasms. (Dictionary of Visual Science, 3d ed)
A visual impairment characterized by the accumulation of fluid under the retina through a defect in the retinal pigment epithelium.
Processes and properties of the EYE as a whole or of any of its parts.
Infection by a variety of fungi, usually through four possible mechanisms: superficial infection producing conjunctivitis, keratitis, or lacrimal obstruction; extension of infection from neighboring structures - skin, paranasal sinuses, nasopharynx; direct introduction during surgery or accidental penetrating trauma; or via the blood or lymphatic routes in patients with underlying mycoses.
Inflammation of the pars plana, ciliary body, and adjacent structures.
The time from the onset of a stimulus until a response is observed.
Agents and endogenous substances that antagonize or inhibit the development of new blood vessels.
Artificial device such as an externally-worn camera attached to a stimulator on the RETINA, OPTIC NERVE, or VISUAL CORTEX, intended to restore or amplify vision.
Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.
The use of photothermal effects of LASERS to coagulate, incise, vaporize, resect, dissect, or resurface tissue.
Inflammation of the choroid as well as the retina and vitreous body. Some form of visual disturbance is usually present. The most important characteristics of posterior uveitis are vitreous opacities, choroiditis, and chorioretinitis.
Type of vision test used to determine COLOR VISION DEFECTS.
Elements of limited time intervals, contributing to particular results or situations.
Loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.
Differential response to different stimuli.
Inanimate objects that become enclosed in the eye.
Benign and malignant neoplasms that arise from the optic nerve or its sheath. OPTIC NERVE GLIOMA is the most common histologic type. Optic nerve neoplasms tend to cause unilateral visual loss and an afferent pupillary defect and may spread via neural pathways to the brain.
Partial or total replacement of the CORNEA from one human or animal to another.
Function of the human eye that is used in bright illumination or in daylight (at photopic intensities). Photopic vision is performed by the three types of RETINAL CONE PHOTORECEPTORS with varied peak absorption wavelengths in the color spectrum (from violet to red, 400 - 700 nm).
Diseases, dysfunctions, or disorders of or located in the iris.
Devices that help people with impaired sensory responses.
Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ECTOPIA LENTIS.
Photosensitive afferent neurons located primarily within the FOVEA CENTRALIS of the MACULA LUTEA. There are three major types of cone cells (red, blue, and green) whose photopigments have different spectral sensitivity curves. Retinal cone cells operate in daylight vision (at photopic intensities) providing color recognition and central visual acuity.
Swelling of the OPTIC DISK, usually in association with increased intracranial pressure, characterized by hyperemia, blurring of the disk margins, microhemorrhages, blind spot enlargement, and engorgement of retinal veins. Chronic papilledema may cause OPTIC ATROPHY and visual loss. (Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p175)
Bleeding in the anterior chamber of the eye.
Organic siloxanes which are polymerized to the oily stage. The oils have low surface tension and density less than 1. They are used in industrial applications and in the treatment of retinal detachment, complicated by proliferative vitreoretinopathy.
Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.
The functional superiority and preferential use of one eye over the other. The term is usually applied to superiority in sighting (VISUAL PERCEPTION) or motor task but not difference in VISUAL ACUITY or dysfunction of one of the eyes. Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS.
A form of ocular misalignment characterized by an excessive convergence of the visual axes, resulting in a "cross-eye" appearance. An example of this condition occurs when paralysis of the lateral rectus muscle causes an abnormal inward deviation of one eye on attempted gaze.
A glucocorticoid given, as the free alcohol or in esterified form, orally, intramuscularly, by local injection, by inhalation, or applied topically in the management of various disorders in which corticosteroids are indicated. (From Martindale, The Extra Pharmacopoeia, 30th ed, p739)
Antibodies from non-human species whose protein sequences have been modified to make them nearly identical with human antibodies. If the constant region and part of the variable region are replaced, they are called humanized. If only the constant region is modified they are called chimeric. INN names for humanized antibodies end in -zumab.
Recording of the average amplitude of the resting potential arising between the cornea and the retina in light and dark adaptation as the eyes turn a standard distance to the right and the left. The increase in potential with light adaptation is used to evaluate the condition of the retinal pigment epithelium.
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.
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.
Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.
A glucocorticoid derivative used topically in the treatment of various skin disorders. It is usually employed as a cream, gel, lotion, or ointment. It has also been used topically in the treatment of inflammatory eye, ear, and nose disorders. (From Martindale, The Extra Pharmacopoeia, 30th ed, p732)
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.
Function of the human eye that is used in dim illumination (scotopic intensities) or at nighttime. Scotopic vision is performed by RETINAL ROD PHOTORECEPTORS with high sensitivity to light and peak absorption wavelength at 507 nm near the blue end of the spectrum.
The coordination of a sensory or ideational (cognitive) process and a motor activity.
A procedure to surgically correct REFRACTIVE ERRORS by cutting radial slits into the CORNEA to change its refractive properties.
Sterile solutions that are intended for instillation into the eye. It does not include solutions for cleaning eyeglasses or CONTACT LENS SOLUTIONS.
Absence of crystalline lens totally or partially from field of vision, from any cause except after cataract extraction. Aphakia is mainly congenital or as result of LENS DISLOCATION AND SUBLUXATION.
Absence of the crystalline lens resulting from cataract extraction.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
Partial or complete loss of vision in one half of the visual field(s) of one or both eyes. Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. Homonymous hemianopsia refers to a visual defect that affects both eyes equally, and occurs either to the left or right of the midline of the visual field. Binasal hemianopsia consists of loss of vision in the nasal hemifields of both eyes. Bitemporal hemianopsia is the bilateral loss of vision in the temporal fields. Quadrantanopsia refers to loss of vision in one quarter of the visual field in one or both eyes.
Exudates are fluids, CELLS, or other cellular substances that are slowly discharged from BLOOD VESSELS usually from inflamed tissues. Transudates are fluids that pass through a membrane or squeeze through tissue or into the EXTRACELLULAR SPACE of TISSUES. Transudates are thin and watery and contain few cells or PROTEINS.
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.
A tricarbocyanine dye that is used diagnostically in liver function tests and to determine blood volume and cardiac output.
The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
The surgical removal of the eyeball leaving the eye muscles and remaining orbital contents intact.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
Inflammation in which both the anterior and posterior segments of the uvea are involved and a specific focus is not apparent. It is often severe and extensive and a serious threat to vision. Causes include systemic diseases such as tuberculosis, sarcoidosis, and syphilis, as well as malignancies. The intermediate segment of the eye is not involved.
The X-shaped structure formed by the meeting of the two optic nerves. At the optic chiasm the fibers from the medial part of each retina cross to project to the other side of the brain while the lateral retinal fibers continue on the same side. As a result each half of the brain receives information about the contralateral visual field from both eyes.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
A group of CORTICOSTEROIDS that affect carbohydrate metabolism (GLUCONEOGENESIS, liver glycogen deposition, elevation of BLOOD SUGAR), inhibit ADRENOCORTICOTROPIC HORMONE secretion, and possess pronounced anti-inflammatory activity. They also play a role in fat and protein metabolism, maintenance of arterial blood pressure, alteration of the connective tissue response to injury, reduction in the number of circulating lymphocytes, and functioning of the central nervous system.
The point or frequency at which all flicker of an intermittent light stimulus disappears.
Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.
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)
Method of making images on a sensitized surface by exposure to light or other radiant energy.
Glial cell derived tumors arising from the optic nerve, usually presenting in childhood.
Ischemic injury to the OPTIC NERVE which usually affects the OPTIC DISK (optic neuropathy, anterior ischemic) and less frequently the retrobulbar portion of the nerve (optic neuropathy, posterior ischemic). The injury results from occlusion of arterial blood supply which may result from TEMPORAL ARTERITIS; ATHEROSCLEROSIS; COLLAGEN DISEASES; EMBOLISM; DIABETES MELLITUS; and other conditions. The disease primarily occurs in the sixth decade or later and presents with the sudden onset of painless and usually severe monocular visual loss. Anterior ischemic optic neuropathy also features optic disk edema with microhemorrhages. The optic disk appears normal in posterior ischemic optic neuropathy. (Glaser, Neuro-Ophthalmology, 2nd ed, p135)
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.
Tumors of the choroid; most common intraocular tumors are malignant melanomas of the choroid. These usually occur after puberty and increase in incidence with advancing age. Most malignant melanomas of the uveal tract develop from benign melanomas (nevi).
Abnormal sensitivity to light. This may occur as a manifestation of EYE DISEASES; MIGRAINE; SUBARACHNOID HEMORRHAGE; MENINGITIS; and other disorders. Photophobia may also occur in association with DEPRESSION and other MENTAL DISORDERS.
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).
Photosensitive protein complexes of varied light absorption properties which are expressed in the PHOTORECEPTOR CELLS. They are OPSINS conjugated with VITAMIN A-based chromophores. Chromophores capture photons of light, leading to the activation of opsins and a biochemical cascade that ultimately excites the photoreceptor cells.
An exudate between the RETINA and CHOROID from various sources including the vitreous cavity, SUBARACHNOID SPACE, or abnormal vessels.
An excessive amount of fluid in the cornea due to damage of the epithelium or endothelium causing decreased visual acuity.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Transmission of gene defects or chromosomal aberrations/abnormalities which are expressed in extreme variation in the structure or function of the eye. These may be evident at birth, but may be manifested later with progression of the disorder.
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
An abrupt voluntary shift in ocular fixation from one point to another, as occurs in reading.
Conditions which affect the structure or function of the pupil of the eye, including disorders of innervation to the pupillary constrictor or dilator muscles, and disorders of pupillary reflexes.
Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
Inflammation of the cornea.
Therapy using oral or topical photosensitizing agents with subsequent exposure to light.
Cognitive disorders characterized by an impaired ability to perceive the nature of objects or concepts through use of the sense organs. These include spatial neglect syndromes, where an individual does not attend to visual, auditory, or sensory stimuli presented from one side of the body.
Failure or imperfection of vision at night or in dim light, with good vision only on bright days. (Dorland, 27th ed)

Zernike representation of corneal topography height data after nonmechanical penetrating keratoplasty. (1/5631)

PURPOSE: To demonstrate a mathematical method for decomposition of discrete corneal topography height data into a set of Zernike polynomials and to demonstrate the clinical applicability of these computations in the postkeratoplasty cornea. METHODS: Fifty consecutive patients with either Fuchs' dystrophy (n = 20) or keratoconus (n = 30) were seen at 3 months, 6 months, and 1 year (before suture removal) and again after suture removal following nonmechanical trephination with the excimer laser. Patients were assessed using regular keratometry, corneal topography (TMS-1, simulated keratometry [SimK]), subjective refraction, and best-corrected visual acuity (VA) at each interval. A set of Zernike coefficients with radial degree 8 was calculated to fit two model surfaces: a complete representation (TOTAL) and a representation with parabolic terms only to define an approximate spherocylindrical surface (PARABOLIC). The root mean square error (RMS) was calculated comparing the corneal raw height data with TOTAL (TOTALRMS) and PARABOLIC (PARABOLICRMS). The cylinder of subjective refraction was correlated with the keratometric readings, the SimK, and the respective Zernike parameter. Visual acuity was correlated with the tilt components of the Zernike expansion. RESULTS: The measured corneal surface could be approximated by the composed surface 1 with TOTALRMS < or = 1.93 microm and by surface 2 with PARABOLICRMS < or = 3.66 microm. Mean keratometric reading after suture removal was 2.8+/-0.6 D. At all follow-up examinations, the SimK yielded higher values, whereas the keratometric reading and the refractive cylinder yielded lower values than the respective Zernike parameter. The correlation of the Zernike representation and the refractive cylinder (P = 0.02 at 3 months, P = 0.05 at 6 months and at 1 year, and P = 0.01 after suture removal) was much better than the correlation of the SimK and refractive cylinder (P = 0.3 at 3 months, P = 0.4 at 6 months, P = 0.2 at 1 year, and P = 0.1 after suture removal). Visual acuity increased from 0.23+/-0.10 at the 3-month evaluation to 0.54+/-0.19 after suture removal. After suture removal, there was a statistically significant inverse correlation between VA and tilt (P = 0.02 in patients with keratoconus and P = 0.05 in those with Fuchs' dystrophy). CONCLUSIONS: Zernike representation of corneal topography height data renders a reconstruction of clinically relevant corneal topography parameters with a marked reduction of redundance and a small error. Correlation of amount/axis of refractive cylinder with respective Zernike parameters is more accurate than with keratometry or respective SimK values of corneal topography analysis.  (+info)

Management of phacolytic glaucoma: experience of 135 cases. (2/5631)

We retrospectively analyzed 135 eyes with phacolytic glaucoma. A trabeculectomy was added to standard cataract surgery if symptoms endured for more than seven days, or if preoperative control of intraocular pressure (IOP) with maximal medical treatment was inadequate. In the early postoperative period, IOP was significantly lower in the combined surgery group (89 eyes) compared to the cataract surgery group (46 eyes) (p < 0.001). At 6 months there was no difference in IOP or visual acuity between the two groups. There were no serious complications related to trabeculectomy. It is reasonable to conclude that in eyes with a long duration of phacolytic glaucoma, addition of a trabeculectomy to cataract surgery is safe, prevents postoperative rise in intraocular pressure and decreases the need for systemic hypotensive medications. A randomized trial is on to further address this question.  (+info)

Effect of pilocarpine on visual acuity and on the dimensions of the cornea and anterior chamber. (3/5631)

The effect of pilocarpine on visual acuity and on the dimensions of the cornea, anterior chamber, and lens were studied in two groups of subjects. Significant changes in ocular tension, corneal curvature, anterior chamber depth, and lens anterior radius were found in a group of 55 glaucomatous eyes as a result of pilocarpine treatment, but there was no change in corneal thickness. Out of 102 glaucomatous eyes 78 became relatively myopic, and this appears to be due to changes in the dimensions of the lens of the eye similar to those occurring in accommodation, as a result of the effect of the drug on the ciliary muscle. The effect of pilocarpine on anterior chamber depth, area, and volume was studied in 125 eyes using a photographic method, and a significant reduction in the dimensions of the anterior chamber was observed as a result of the administration of pilocarpine. A significant correlation between depth and volume was also noted and the implications of this are discussed.  (+info)

De novo lesions in presumed ocular histoplasmosis-like syndrome. (4/5631)

Two patients with multifocal choroiditis similar or identical to POHS are presented. Colour photographs and fluorescein angiography document the occurrence of de novo lesions in the originally involved eye. The cases also demonstrate the development of new choroidal lesions within the originally involved eye, the early evolution of the "basic choroidal lesion", and the need for fluorescein angiography for visualizing the underlying choroidal lesion.  (+info)

Prognosis of perforating eye injury. (5/5631)

The assessment of visual function in a series of 130 consecutive patients of perforating eye injuries, revealed that visual acuity of 6/12 or better was regained in 63 per cent, between 6/60 and 6/18 in 9-2 per cent, less than 6/60 in 15-3 per cent, and enucleation was necessary in 9-2 per cent. In 3 per cent, the eyes were retained as blind, symptomfree, and cosmetically satisfactory organs. Two eyes were found to develop complete traumatic aniridia. None in the series was found to have sympathetic ophthalmitis.  (+info)

Vitrectomy in 125 eyes with diabetic vitreous haemorrhage. (6/5631)

A total of 125 consecutive eyes, all registered blind with diabetic vitreous haemorrhage, underwent pars plana vitrectomy with the vitrophage. Sixty-six per cent experienced some improvement in their visual acuity; 24 per cent were unchanged and 10 per cent were worse postoperatively. The major surgical complication was controllable haemorrhage (23 per cent). No retinal dialysis occurred. Significant postoperative complications were transient (71 per cent) and persistent (11 per cent) corneal oedema, early (8 per cent) and late (13 per cent) vitreous haemorrhage, transient (30 per cent) and persistent (6 per cent) rise in intraocular pressure, and rubeosis iridis (5 per cent).  (+info)

A prospective study of xenon arc photocoagulation for central retinal vein occlusion. (7/5631)

Twenty patients with central retinal vein occlusion were randomly divided into two groups in a prospective study to evaluate the effects of xenon are photocoagulation in central retinal vein occlusion. The patients in one group were treated with 360 degrees scatter xenon photocoagulation and the others received no treatment. The average follow-up was 18 months. There were no cases of rubeosis or neovascular glaucoma in the treated group. Two patients in the untreated group developed rubeosis with subsequent neovascular glaucoma. There was no significant difference in the visual prognosis or in fundus neovascularization between the groups.  (+info)

Characteristics of discrepancies between self-reported visual function and measured reading speed. Salisbury Eye Evaluation Project Team. (8/5631)

PURPOSE: Visual impairment is a risk factor for morbidity in the elderly and is often screened for by self-report. This study evaluates whether there are subsets for whom there is a discrepancy between self-reported and measured function. METHODS: The prevalence of a discrepancy between self-reported difficulty reading a newspaper and measured reading speed was determined in 2520 community-based men and women, aged 65 to 84 years, and the discrepant group characterized by polychotomous regression. RESULTS: Of subjects who reported minimal difficulty reading a newspaper, 10.8% (227/2107) read newsprint-sized text (0.21 degrees) more slowly than 80 words/min, a level previously shown to be necessary for sustained reading. Poor visual acuity, presence of psychiatric symptoms, and less satisfaction with vision were associated with being in the group that read slowly and reported difficulty with reading. Better cognition, better visual acuity, more years of education, white race, and fewer psychiatric symptoms were associated with being in the group that read more quickly and reported minimal difficulty. When reading the text size at which subjects read their fastest, only 2.6% of those with minimal difficulty remained discrepant. These individuals were more likely to have less education, be male, be African American, and have poorer cognitive status than those who did not remain discrepant. CONCLUSIONS: A subset of the elderly population have a substantial discrepancy between self-reported reading difficulty and measured reading speed. In some, this discrepancy may be based on underlying expectations and experiences, and in others it may represent a transition from no visual impairment to visual impairment.  (+info)

In the Journal of Refractive Surgery from the August of 2018 issue, the article written by Rohit Shetty M.D. Et. al titled Wavefront-Guided LASIK Has Comparable Ocular and Corneal Aberrometric Outcomes but Better Visual Acuity Outcomes Than SMILE in Myopic Eyes compares Wavefront Guided LASIK (WFG) with small incision lenticule extraction (SMILE).. In this study, 48 SMILE eyes were completed and 58 WFG LASIK eyes were completed. The eyes were re-tested at the one month and 3 month post-operative periods using corneal topography and anterior aberration assessment. Both WFG LASIK and SMILE had comparable safety and efficacy. However, it was noticed that more WFG LASIK eyes had achieved an uncorrected distance vision of 20/16 after surgery than SMILE eyes. WFG LASIK and SMILE had similar aberrometric outcomes but WFG has better postoperative visual acuity. The experience was small pupil size, internal aberrations and wound healing can enable similar outcomes with both procedures.. Here at ...
PURPOSE: To characterize the effect of passive vertical head motion on dynamic visual acuity of young, normally sighted subjects wearing telescopic spectacles, and to relate this to the velocity of images on the retina. METHODS: Static visual acuity was measured without motion. Dynamic visual acuity was measured during vertical, sinusoidal motion of either optotypes or of a servo-driven rotating chair in which subjects were seated. Dynamic visual acuity for head motion was measured unaided, as well as with 1.9X, 4X, and 6X telescopic spectacles. Vertical eye movements were recorded using magnetic search coils. RESULTS: During optotype motion, acuity declined with increasing velocity to a minimum of approximately 20/200 at 100 degrees/sec. Pursuit gain (eye velocity/optotype velocity) for moving optotypes was low except for optotype velocities of 20 degrees/sec of less. Dynamic visual acuity without telescopic spectacles was not sensitive to head motion. Static visual acuity improved with ...
Purpose: : To determine early visual acuity outcomes after beginning Macugen therapy as a salvage treatment for subfoveal CNV in AMD patients. Methods: : A retrospective chart review of visual acuity outcomes of AMD patients who underwent Macugen salvage therapy (prior treament of CNV or chronic PED) for subfoveal CNV by one physician. All patients underwent the same intravitreal injection technique and were positioned supine for 25 minutes post-injection. Patients with at least three months follow-up were eligible for inclusion. Results: : There were 13 patients with subfoveal CNV due to AMD that received Macugen as a salvage therapy. Patient ranged in age from 72 to 86 years old. Prior treatments included PDT in five patients, radiation therapy in one patient and systemic retinoid therapy in another patient. Six other patients had a history of chronic PEDs with CNV. Baseline visual acuity ranged from 20/ 50 to counts fingers. Visual acuity was within two lines of baseline in 9/13 (69%) eyes at ...
Bilateral vestibulopathy (BVP) can affect visual acuity in dynamic conditions, like walking. This can be assessed by testing Dynamic Visual Acuity (DVA) on a treadmill at different walking speeds. Apart from BVP, age itself might influence DVA and the ability to complete the test. The objective of this study was to investigate whether DVA tested while walking, and the drop-out rate (the inability to complete all walking speeds of the test) are significantly influenced by age in BVP-patients and healthy subjects.Forty-four BVP-patients (20 male, mean age 59 years) and 63 healthy subjects (27 male, mean age 46 years) performed the DVA test on a treadmill at 0 (static condition), 2, 4 and 6 km/h (dynamic conditions). The dynamic visual acuity loss was calculated as the difference between visual acuity in the static condition and visual acuity in each walking condition. The dependency of the drop-out rate and dynamic visual acuity loss on BVP and age was investigated at all walking speeds, as well ...
To evaluate the correlation between visual acuity improvement and vision-related QOL after ranibizumab treatment in Japanese patients with AMD. In this one-year prospective, interventional, open-label, multicenter study involving four sites, patients with neovascular AMD were enrolled and observed for 12 months. Treatment-naïve patients received 0.5 mg ranibizumab as needed after three initial monthly doses. The best corrected visual acuity (BCVA) and central macular thickness (CMT) were measured at every visit. Evaluations with the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and patient satisfaction questionnaire were performed at baseline and 3 and 12 months after initial treatment. The primary endpoint was change in BCVA and QOL 3 months after ranibizumab treatment. QOL outcomes were also assessed in the better and poor BVCA subgroups. The study enrolled 100 patients. The mean logMAR BCVA after treatment improved significantly from 0.43 to 0.30 at 3 months (p| 0.0001),
To evaluate the correlation between visual acuity improvement and vision-related QOL after ranibizumab treatment in Japanese patients with AMD. In this one-year prospective, interventional, open-label, multicenter study involving four sites, patients with neovascular AMD were enrolled and observed for 12 months. Treatment-naïve patients received 0.5 mg ranibizumab as needed after three initial monthly doses. The best corrected visual acuity (BCVA) and central macular thickness (CMT) were measured at every visit. Evaluations with the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and patient satisfaction questionnaire were performed at baseline and 3 and 12 months after initial treatment. The primary endpoint was change in BCVA and QOL 3 months after ranibizumab treatment. QOL outcomes were also assessed in the better and poor BVCA subgroups. The study enrolled 100 patients. The mean logMAR BCVA after treatment improved significantly from 0.43 to 0.30 at 3 months (p| 0.0001),
There is a multitude of options available for the clinical measurement of visual acuity. Variations in the characteristics of the tests and their administration can affect the scores of visual acuity. And the test task influences acuity scores can be very dependent on the nature of any ocular disorders.. Acuity scores are affected by whether the optotypes are Landolt rings, tumblingEs various families of letters, numbers, pictures or symbols. Reading acuity tests might include flowing text or unrelated words.. Other acuity tests use gratings, checkerboards or vanishing optotypes. Optotypes might be presented singly, in rows, in chart format and sometimes flanking bars are used. The visual acuity score is invariably a measure of angle dependent on the viewing distance and the size of a specific feature of the test target, but it is not always clear what that specific feature should be.. There is no one true visual acuity. All presentations of visual acuity results should include a full ...
Aim: To investigate and compare the effect of Fresnel prisms on visual acuity in photopic and mesopic conditions.. Methods: Twelve participants aged between 18 and 26 years were recruited who had good visual acuity and normal binocular single vision. Monocular visual acuity was measured with three strengths of base-out Fresnel prisms (5Δ, 15 Δ, 30 Δ) and without a Fresnel prism. The right eye was tested in all participants. This was assessed at 60 cd/m2 and 1 cd/m2. Participants adapted to 1 cd/m2 for 5 min before being tested at this luminance, and those tested at 1 cd/m2 first were allowed to adapt to normal room lighting (60 cd/m2) for 2 min before being tested at this level of lighting.. Results: A two-factor analysis of variance (ANOVA) revealed that both increased Fresnel prism strength (F11,3 = 204.762, p , 0.0001) and luminance (F11,1 = 343.303, p , 0.0001) significantly reduced visual acuity. There was no interaction between prism strength and lighting condition. The reduction in ...
PHILADELPHIA - A hand-held internally illuminated ETDRS device provided accurate and repeatable visual acuity measurements, according to a study presented here. Despite the FDA requiring ETDRS vision in registered trials, still the vast majority of published studies in the ophthalmic literature use Snellen visual acuity, Ehsan Rahimy, MD, said at the Wills Eye Annual Conference. There are multiple reasons for the lack of widespread incorporation of the ETDRS system, including the increased time it takes to measure these acuities. … A novel back-lit handheld ETDRS vision meter may allow for (Read more...) Full Story →. ...
Patient with Macular Disease, Good Visual Acuity, and Central Visual Field Disruption and Significant Difficulties with Activities of Daily Living, Online,
Recently, there has been heightened interest in suggestions of enhanced visual acuity in autism spectrum disorders (ASD) which was sparked by evidence that was later accepted to be methodologically flawed. However, a recent study that claimed children with ASD have enhanced visual acuity (Brosnan et al. in J Autism Dev Disord 42:2491-2497, 2012) repeated a critical methodological flaw by using an inappropriate viewing distance fora computerised acuity test, placing the findings in doubt. We examined visual acuity in 31 children with ASD and 33controls using the 2 m 2000 Series Revised Early Treatment Diabetic Retinopathy Study chart placed at twice the conventional distance to better evaluate possible enhanced acuity. Children with ASD did not demonstrate superior acuity. The current findings strengthen the argument that reports of enhanced acuity in ASD are due to methodological flaws and challenges the reported association between visual acuity and systemising type behaviours.. ...
Visual Acuity - Think Big, Think Bold In our 2013 awareness week we focused on poor visual acuity in people with Downs syndrome and the impact is has upon daily life. Fact: Vision is poorer in all people with Downs...
A Bayesian model of Snellen visual acuity (VA) has been developed that, as far as we know, is the first one that includes the three main stages of VA: (1) optical degradations, (2) neural image representation and contrast thresholding, and (3) character recognition. The retinal image of a Snellen test chart is obtained from experimental wave-aberration data. Then a subband image decomposition with a set of visual channels tuned to different spatial frequencies and orientations is applied to the retinal image, as in standard computational models of early cortical image representation. A neural threshold is applied to the contrast responses to include the effect of the neural contrast sensitivity. The resulting image representation is the base of a Bayesian pattern-recognition method robust to the presence of optical aberrations. The model is applied to images containing sets of letter optotypes at different scales, and the number of correct answers is obtained at each scale; the final output is ...
The Visual Acuity Measurements IOD is used to capture a patients visual acuity relative to that of a reference standard patient under given viewing conditions (distance, lighting, etc.).
Percentage of patients aged 18 years and older with a diagnosis of uncomplicated cataract who had cataract surgery and no significant ocular conditions impacting the visual outcome of surgery and had best-corrected visual acuity of 20/40 or better (distance or near) achieved within 90 days following the cataract surgery
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Results We assessed a cohort of 140 patients with PCG (235 eyes) with an average follow-up of 127±62.8 months (range 60-400 months). Overall, the proportion of eyes with good visual acuity was 89 (37.9%), those with fair visual acuity between 6/60 and 6/18 was 41 (17.4%), and those with poor visual acuity (≤6/60) was 105 (44.7%). We found a significant difference (p=0.047) between neonatal and infantile patients with PCG whereby the neonatal cohort fared worse off in terms of visual morbidity. On Kaplan-Meier analysis, the cumulative probability of survival of a visual acuity of 6/18 or better was more among the infantile PCG in comparison to the neonatal PCG (p=0.039) eyes, and more among the bilateral than the unilateral affected eyes (p=0.029). Amblyopia was the most important cause for poor visual acuity as shown on a Cox proportional-hazards regression model. ...
Background/Aims: This was a cross-sectional survey to find the prevalence of visual impairment and eye diseases among adults with Down syndrome (DS) in Hong Kong. Methods: 91 DS patients over the age of 30 were recruited through the Hong Kong Down Syndrome Association. Each patient was provided with a complete ophthalmological assessment including best corrected visual acuity, refraction, slit lamp and fundus examination. Results: In our sample, 56.6% had normal vision to mild vision impairment, 33.7% and 7.2% had moderate and severe vision impairment, respectively, and 2.4% were blind. The mean presenting distant LogMAR visual acuity was 0.66 (Snellen equivalent 20/90), and the best corrected LogMAR visual acuity was 0.48 (Snellen equivalent 20/60). Significant refractive errors were found in 86.3% of the eyes, with spherical equivalent corrections ranging from -23.25D to +3.00D. Myopia and astigmatism were prevalent and found in 59.3% and 72.7% of the eyes, respectively. Blepharitis and ...
Methods Patients with maculopathies (retinal vein occlusion, macula-off retinal detachment, dry age-related macular degeneration and wet age-related macular degeneration) and good letter acuity (VA ≥20/30) were included. The qCSF method uses an intelligent algorithm to measure CSF across multiple spatial frequencies. All maculopathy eyes combined and individual macular disease groups were compared with healthy control eyes. Main outcomes included area under the log CSF (AULCSF) and six CS thresholds ranging from 1 cycle per degree (cpd) to 18 cpd. ...
Background/aimsConventional Logarithm of the Minimum Angle of Resolution (logMAR) acuity is the current gold standard for assessing visual function in age-related macular degeneration (AMD). However, visual acuity (VA) often remains normal when measured with these charts, even with advanced retina
Explore visual acuity tests and the Jaeger eye chart. Learn about the various eye charts and tests that can be used to determine your visual acuity.
This page includes the following topics and synonyms: Visual Acuity, Vision Screening, Snellen Chart, ETDRS Visual Acuity Chart, Rosenbaum Chart, HOTV Card.
Visual acuity (VA) commonly refers to the clarity of vision. Visual acuity is dependent on optical and neural factors, i.e., (i) the sharpness of the retinal focus within the eye, (ii) the health and functioning of the retina, and (iii) the sensitivity of the interpretative faculty of the brain. A common cause of low visual acuity is refractive error (ametropia), or errors in how the light is refracted in the eyeball. Causes of refractive errors include aberrations in the shape of the eyeball, the shape of the cornea, and reduced flexibility of the lens. Too high or too low refractive error (in relation to the length of the eyeball) is the cause of nearsightedness (myopia) or farsightedness (hyperopia) (normal refractive status is referred to as emmetropia). Other optical causes are astigmatism or more complex corneal irregularities. These anomalies can mostly be corrected by optical means (such as eyeglasses, contact lenses, laser surgery, etc.). Neural factors that limit acuity are located in ...
4SB Beyoğlu Göz Eğitim ve Araştırma Hastanesi Klinik Şefi, İstanbul, Prof. Dr. Purpose: To present the results of the technique in which triamcinolone assisted internal limiting membrane (ILM) peeling during pars plana vitrectomy (PPV) for idiopathic macular hole.. Materials and Methods: 0.1-0.2 ml triamcinolone (Kenakort 40 mg), diluted 1:5, was carefully injected over the macular area under the fluid following core vitrectomy via standard 3-port sclerotomy in 11 patients (4 female, 7 male; mean age 67±8 years). ILM was peeled by using a forceps over the retinal surface in the form of maculorhexis while triamcinolone made ILM visible by specifically adhering it. C3F8 gas was used as internal tamponade at the end of surgery. Anatomic success was assessed by the help of optical coherence tomography and functional success was assessed by using Snellen visual acuity charts. Snellen visual acuity values were converted to logMAR equivalents for the statistical comparisons.. Results: Mean ...
Visual acuity should be reported on the basis of how the measurement was determined. For example, using the Snellen fraction with English units, 20/20 or 20/100 indicates that the person being evaluated can see at 20 ft what a person with normal visual acuity can see at 20 ft or at 100 ft, respectively. The equivalent metric measurements for visual acuity are 6/6 and 6/30, respectively ...
Purpose Early detection of abnormal visual acuity (VA) is crucial in the identification and management of ocular and visual abnormalities in infants. Currently, the Teller Acuity Cards (TACs) are considered the gold standard for clinical testing and are effective in obtaining a quick estimate of an infants VA, but they have certain drawbacks. They rely on a subjective assessment of the babys looking behavior. Despite this, TACs have been found to have good validity and repeatability. The current study investigates a new method to objectively assess visual acuity in infants, which is uses a video gaze tracker (GT) and computer-generated stimuli, developed in the lab of M. Eizenman at the University of Toronto. The purpose was to validate this method in adults and infants against current clinical VA tests. Visual scanning patterns were measured by the GT system that requires minimal subject cooperation in adult and infant populations. The targets were judged as seen when the relative fixation ...
Your optometrist will perform a comprehensive eye exam. One of the factors that your doctor uses to evaluate your vision is the visual acuity exam. To determine a patients visual acuity, the optometrist will ask you to read letters of various sizes from a certain distance away. This test determines the acuity of each eye written as a fraction.
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Fingerprint Dive into the research topics of Longitudinal comparison of visual acuity as measured by the ETDRS chart and by the potential acuity meter in eyes with macular edema, and its relationship with retinal thickness and sensitivity. Together they form a unique fingerprint. ...
There is limited direct evidence on the effectiveness of screening for visual impairment in the primary care setting. Three fair-quality cluster randomized clinical trials (RCTs) found no difference in vision and other clinical or functional outcomes between vision screening (as part of a multicomponent screening) with visual acuity testing or questions compared with usual care, no vision screening, or delayed screening.13-15 The application of this evidence to screening in a primary care setting has limitations. Issues with the study methods include failure to report allocation concealment, lack of intention-to-treat analysis, and unclear blinding of outcome assessors. Other limitations relevant to the primary care setting include that the recommended interventions are provided by eye care specialists and that many patients do not get the recommended glasses.. Consistent evidence shows that most older adults with a refractive error can achieve visual acuity better than 20/40 with refractive ...
Measurement of uncorrected (without spectacles or other visual corrective devices) and best-corrected (with spectacles or other visual corrective devices)visual acuity at both near and distance. Visual Acuity (VA) is measured in logMAR. LogMAR is the logarithm of the minimum angle of resolution. A lower logMAR value indicates better visual acuity ...
Among 518 operated patients, 426 (82.2%) could be contacted and 334 (64.4% of operated patients) completed the examinations. The mean age was 74.1 ± 8.8 years and 62.9% were women. Postoperative uncorrected visual acuity was available in 372 eyes. Among them, uncorrected visual acuity was ≥6/18 in 278 eyes (74.7%) and ,6/60 in 60 eyes (16.1%), and 323 eyes (86.8%) had pinhole visual acuity ≥ 6/18 and 38 eyes (10.2%) had pinhole visual acuity , 6/60. Main causes of visual impairment were uncorrected refractive error (63.9%) and comorbid eye disease (24.5%). Comorbid eye diseases associated with pinhole visual acuity , 6/60 (n = 23, 6.2%) included glaucoma, other optic nerve atrophy, vitreous haemorrhage and retinal detachment. ...
To investigate the influence of intraocular lens subsurface nanoglistenings (SSNGs) on functional visual acuity (FVA), thirty-nine eyes of 29 patients were examined in this study. The SSNG group comprised 19 eyes of 14 patients (75.7± 5.4 years, mean ± standard deviation), and the control group comprised 20 eyes of 15 patients (73.6 ± 6.5 years). The SSNGs were diagnosed on the basis of the typical whitish IOL appearance upon slit-lamp examination and results of densitometry regarding surface light scattering using Scheimpflug images. The FVA measurement system (AS-28; Kowa, Aichi, Japan) was used to examine changes in continuous visual acuity (VA) over time, and visual function parameters such as FVA, visual maintenance ratio (VMR), maximum VA, minimum VA, standard deviation of VA, and number of blinks were assessed. The results were compared between the SSNG and control groups, and correlations of FVA parameters with the intensity of surface light scattering, time after surgery, and age were also
Monocular and Binocular Unaided (UCVA) and Best Corrected Visual Acuity (BCVA) will be measured at 6m in LogMAR units under photopic conditions (85cd/m2).. Subjective Refraction will be performed to establish any residual refractive error will for distance, intermediate and near.. Defocus Profiles (visual acuity over imposed defocus) are measured for each patient. The patient observes the 6m LogMAR chart through best distance correction, then defocusing is achieved by the addition of pairs of lenses from +2.00D to -4.00D in 0.50D steps.. The LogMAR acuity will be recorded and the data plotted.. Contrast Sensitivity will be evaluated monocularly under photopic (85cd/m2) conditions and mesopic (4cd/m2) using the Pelli-Robson Contrast Sensitivity Chart.. Near and intermediate performance will be evaluated using the Radner Reading Charts to assess acuity (LogRAD units) and reading speed in photopic conditions 85cd/m2 ...
In a real-world setting, the majority of DME patients with very good VA maintained vision at 12 months, regardless of whether the DME was treated or not. This study supports close observation of eyes with DME and very good VA with consideration of treatment when a one line drop in vision is observed …
Stratview Research is about to publish a report on Refractive Correction and Visual Acuity Market, which will highlight opportunities for new and established players in the market during the forecast period 2019 - 2025. Not consuming a balanced diet and leading an unhealthy lifestyle are the crucial reasons for the increasing number of people suffering from different visual difficulties. Bowls of fresh leafy vegetables and fruits are now replaced with packaged food and the 24 hours interaction of the eyesight with the smartphone and computer screen is making them sick by each passing day.. Request a sample for the report at For visual acuity testing, in most of the market, the conventional or manual chart projector is used. Stratview Research has analyzed and stated in its upcoming report that the optometrists today have the choice between Automated Chart Projector, Polarized Digital Acuity ...
PURPOSE: The aim of this study was to determine whether typical abnormalities seen on autofluorescence (AF) imaging in patients with macular telangiectasia (MacTel) type 2 are correlated with visual acuity at presentation and with progression of visual loss over a 2-year follow-up period. METHODS: A subgroup of 218 patients (413 eyes) enrolled in the MacTel study that underwent AF imaging was included in the present study. Images were graded at the Moorfields Eye Hospital Reading Center. Recorded AF abnormalities at baseline and at 2 years included the presence of increased AF because of loss of masking at the central macula, localized decreased AF at the end of a retinal vessel, and large area of decreased AF. Best-corrected visual acuity was measured using the Early Treatment for Diabetic Retinopathy chart at baseline and after 2 years. Statistical associations were sought by means of a generalized linear model. RESULTS: Presence of increased macular AF (P = 0.004), a large area of decreased AF (P | 0
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INTRODUCTION: Astronauts experience alterations in gaze control as a result of adaptive changes in eye-head coordination produced by microgravity exposure. This may lead to potential changes in postflight visual acuity during head and body motion. METHODS: We gathered dynamic visual acuity (DVA) data from 14 astronauts and cosmonauts after long-duration (approximately 6 mo) stays in space. Walking was used to induce self-motion and visual acuity was determined by sequentially presenting Landolt ring optotypes on a computer display placed 4 m in front of subjects. Acuity assessments were made while seated (static condition) and walking (dynamic condition) at 6.4 km x h(-1) on a motorized treadmill. In each condition, a psychophysical threshold detection algorithm minimized the required number of optotype presentations by maximizing the amount displayed around the subject's acuity threshold. The difference between static and dynamic acuity measures provided a metric of change in the ...
Ziel und Zweck der Arbeit: In dieser Arbeit wurden die Visusergebnisse der häufig verwendeten ETDRS- und Landoltring-Sehzeichentafeln mit denen des Freiburg Visual Acuity Test (FrACT) verglichen. Zusätzlich wird ein Hauptaugenmerk auf den Vergleich zweier Eingabemethoden für den Freiburg Visual Acuity Test gelegt, um ein mögliches Verbesserungspotenzial dieser aufzudecken. Bei den verwendeten Eingabemethoden handelte es sich um einen dreh- und fühlbaren Landolting (FrACTh) und die Eingabe mit einer modifizierten Zahlentastatur (FrACTk). Ziel dieser Studie war es, quantitative Aussagen zu folgenden Messgrößen zu ermitteln: (i) die Übereinstimmung des FrACTk und FrACTh, (ii) deren Reproduzierbarkeit, (iii) die Übereinstimmung der Visusergebnisse aller verwendeter Tests und (iv) deren Reproduzierbarkeit zu quantifizieren. Material und Methoden: Als Probanden nahmen an der Studie 25 augengesunde Studenten der Hochschule Aalen (19 - 28 Jahre) teil. Der Fernvisus jedes Probanden lag, mit
Effect of hemodialysis on visual acuity, intraocular pressure, and macular thickness in patients with chronic kidney disease Elias Chelala,1,2,* Ali Dirani,1,2,* Ali Fadlallah,1,2 Elise Slim,1,2 Youssef Abdelmassih,1,2 Henry Fakhoury,3 Patrick Baz,1,2 Riad Bejjani1,2 1Faculty of Medicine, Saint-Joseph University, 2Hôtel-Dieu de France Hospital, Saint-Joseph University, 3Eye and Ear Hospital, Beirut, Lebanon *These two authors contributed equally to this work Background: The aim of this study was to evaluate the effects of hemodialysis (HD) on visual acuity, intraocular pressure (IOP), and central foveal thickness (CFT) in patients with chronic kidney disease.Materials and methods: Forty-nine eyes from 49 chronic kidney-disease patients were analyzed. Causes of chronic kidney disease included diabetes mellitus (n=9 patients), hypertensive nephrosclerosis (n=15 patients), and other causes (n=25 patients). All patients underwent HD in the Dialysis Unit of Hôtel-Dieu de France Hospital. Best
MassVAT HOTV Logarithmic Visual Acuity Chart. HOTV Optotypes can be used for testing preliterate children and illiterate patients. Buy online.
Purpose: To compare the efficacy and safety of ranibizumab and bevacizumab intravitreal injections to treat neovascular age-related macular degeneration (nAMD). Design: Multicenter, noninferiority factorial trial with equal allocation to groups. The noninferiority limit was 3.5 letters. This trial is registered (ISRCTN92166560). Participants: People | 50 years of age with untreated nAMD in the study eye who read | 25 letters on the Early Treatment Diabetic Retinopathy Study chart. Methods: We randomized participants to 4 groups: ranibizumab or bevacizumab, given either every month (continuous) or as needed (discontinuous), with monthly review. Main Outcome Measures: The primary outcome is at 2 years; this paper reports a prespecified interim analysis at 1 year. The primary efficacy and safety outcome measures are distance visual acuity and arteriothrombotic events or heart failure. Other outcome measures are health-related quality of life, contrast sensitivity, near visual acuity, reading index,
TY - JOUR. T1 - The effects of target wavelength on dynamic visual acuity under photopic and scotopic viewing. AU - Long, G. M.. AU - Garvey, Philip M.. PY - 1988/1/1. Y1 - 1988/1/1. N2 - The effects of target wavelength on the resolution of moving targets were investigated over a range of target velocities under both photopic and scotopic viewing conditions. The wavelength of the photopically matched targets had no effect on dynamic acuity under the bright background condition. However, with low background luminance the wavelength of the targets had pronounced effects, with blue targets producing far superior resolution and red targets, the poorest resolution. These results were maintained over both 250- and 400-ms target durations and regardless of whether initial target position was foveal or peripheral. The likely contribution of the rod system to dynamic visual acuity under some conditions is proposed, and possible implications for applied settings are discussed.. AB - The effects of target ...
Early treatment for Type 1 high-risk prethreshold eyes improved visual acuity outcomes at 6 years of age. Early treatment for Type 2 high-risk prethreshold eyes did not. Application to Clinical Practice Type 1 eyes, not Type 2 eyes, should be treated early. These results are particularly important c …
TY - JOUR. T1 - Does weight lifting improve visual acuity? A replication of Gonzalo-Fonrodona and Porras (2013). AU - Yonemitsu, Fumiya. AU - Sung, Yubin. AU - Naka, Kyoko. AU - Yamada, Yuki. AU - Marmolejo-Ramos, Fernando. N1 - Publisher Copyright: © 2017 The Author(s). Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 2017/8/1. Y1 - 2017/8/1. N2 - Objective: A physical effort such as lifting up a weight affects our perception and cognition. A previous study reported in two experiments that weight lifting improves visual acuity. In the previous study, participants visual acuity was higher while lifting weights than while resting. Moreover, via a case study, that study further showed that the heavier the weight, the better the visual acuity. These experiments, although interesting, lacked methodological details and thorough statistical analyses. We thus conducted experiments similar to these two previous ones that mitigated these issues. Results: Although our results of ...
Circulating monocytes and B-lymphocytes in neovascular age-related macular degeneration Sven Magnus Hector,1 Torben Lykke Sørensen1,2 1Clinical Eye Research Unit, Zealand University Hospital, Roskilde, 2Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark Background: Individuals with neovascular age-related macular degeneration (AMD) have altered number and distribution of retinal macrophages and show changes in circulating antibodies. We wanted to investigate the corresponding precursors, with subpopulations. We therefore measured monocyte and B-lymphocyte populations in individuals with neovascular AMD.Design: This was an observational case–control study.Participants or samples: A total of 31 individuals with neovascular AMD and 30 healthy age-matched controls were included.Methods: Patients and controls were interviewed, and ophthalmological examination included visual acuity assessment using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart,
Six months postoperatively, we measured uncorrected and spectacle-corrected distance, intermediate and near visual acuity. Uncorrected and spectacle-corrected near visual acuity was easured using a Rosenbaum-Jaeger reading chart at 35 cm, and intermediate visual acuity at 60 cm. The chart was directly illuminated by a 60 W lamp. Uncorrected and spectacle- corrected distance visual acuity was measured using a Snellen chart fro 6 m. Visual acuity values were converted in logarithmic scale for statistical analysis. A Scheimpflug imaging system (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany) was used to evaluate IOL tilt and decentration according to de Castro et al (10) as follows: IOL decentration is obtained from the distance between the IOL center and pupillary axis. Positive horizontal coordinates stand for nasal in the right eye and temporal in the left eye. Positive vertical coordinates stand for superior decentration, and negative for inferior decentration. By eliminating positive and ...
Purpose: To investigate the effects on near visual acuity, reading speed, central visual field and related quality of life of ranibizumab treatment of wet age-related macular degeneration (AMD). Methods: The study was a prospective, non-comparative consecutive case series, followed for 3 months and investigator-driven. Thirty eyes of 30 patients with wet AMD were included, mean age 75 years (range 69-95 years). In addition to a full ophthalmological examination - including best-corrected visual acuity (BCVA; Early Treatment Diabetic Research Study chart), fundus biomicroscopy, fundus photography, fluorescein angiography, indocyanine green angiography (occult cases) and ocular coherence tomography - near visual acuity, reading speed, central visual field and quality of life for related activities were also investigated at baseline and at 3 months after ranibizumab treatment. Results: Mean BCVA increased from 62 +/- 11 to 66 +/- 14 letters at 3 months (7%; p = 0.018). Near vision improved from 9 ...
Purpose:. Eye charts examine the persons ability to distinguish black letters or numbers on a white background. Snellen chart, first of its kind was developed by the Dutch eye doctor Hermann Snellen in the 1860s. There are many different variations of eye charts, but in general they show 11 rows of capital letters. In every line the letters get progressively smaller. The visual acuity is examined at 6 metres or 20 feet. People are more and more used to use phones on a daily basis; this is why they would also be more familiar with the reading text on the smartphones than on traditional paper charts. Test measures the clarity of vision or its ability to resolve detail. Client´s visual acuity depends on the accuracy of the retinal focus, the integrity of the eye´s neural elements and the interpretive faculty of the brain. Visual acuity at near should be tested in all clients, regardless of the client´s age. Reading test is used to verify that the prescribed correction is appropriate. When ...
Purpose:. Eye charts examine the persons ability to distinguish black letters or numbers on a white background. Snellen chart, first of its kind was developed by the Dutch eye doctor Hermann Snellen in the 1860s. There are many different variations of eye charts, but in general they show 11 rows of capital letters. In every line the letters get progressively smaller. The visual acuity is examined at 6 metres or 20 feet. People are more and more used to use phones on a daily basis; this is why they would also be more familiar with the reading text on the smartphones than on traditional paper charts. Test measures the clarity of vision or its ability to resolve detail. Client´s visual acuity depends on the accuracy of the retinal focus, the integrity of the eye´s neural elements and the interpretive faculty of the brain. Visual acuity at near should be tested in all clients, regardless of the client´s age. Reading test is used to verify that the prescribed correction is appropriate. When ...
TY - JOUR. T1 - Predictors of visual outcome following surgical resection of medial sphenoid wing meningiomas. AU - Chaichana, Kaisorn L.. AU - Jackson, Christopher. AU - Patel, Amar. AU - Miller, Neil R.. AU - Subramanian, Prem. AU - Lim, Michael. AU - Gallia, Gary. AU - Olivi, Alessandro. AU - Weingart, Jon. AU - Brem, Henry. AU - Quinones-Hinojosa, Alfredo. PY - 2012. Y1 - 2012. N2 - Objective: Medial sphenoid wing meningiomas (SWMs) are relatively common tumors that are associated with significant morbidity and mortality, primarily from their anatomic proximity to many critical neurological and vascular structures. A major complication is visual deterioration. This study aimed to identify predictors of visual outcome following medial SWM resection. Design: Retrospective, stepwise multivariate proportional hazards regression analysis. Setting: Johns Hopkins Hospital. Participants: All patients who underwent medial SWM resection from 1998 to 2009. Main Outcome Measures: Visual function. ...
A terminal device includes an image data holding unit that holds examination image data, an image output processing unit that outputs the examination image data to a visual field/visual acuity examination device, a display unit that displays an image, and a display control unit that generates an examination image based on the examination image data and displays the examination image on the display unit. The visual field/visual acuity examination device includes a light source unit that emits a light beam, an image input unit that inputs the examination image data from the terminal device, a control unit that generates an image light beam based on the input examination image data and controls emission of the image light beam from the light source unit, a scanning mirror that scans the image light beam to generate an examination image light beam, and a projection unit that projects the examination image light beam as the examination image on an eyeball of a test subject. The examination image data
1. Introduction 1.1 Amblyopia 1.1.1 Definition Amblyopia or „lazy eye‟ has conventionally been defined as a unilateral or bilateral decrease of visual acuity caused by deprivation of pattern vision or abnormal binocular interaction, for which no cause can be detected by physical examination of the eye and which in some cases can be reversed by therapeutic measures (1). Clinically, amblyopia is defined as a reduction in best-corrected visual acuity to less than 6/9 monocularly in Snellen optotype or as a two-line difference or more in best-corrected visual acuity between the eyes in LogMAR optotype. This compares with findings in normal subjects, in which the interocular difference in best-corrected visual acuity has been found to be less than two lines (0.2 LogMAR optotype) in both infants and adults (2). However, clinical definitions are debated with different studies using different inclusion criteria for the amblyopic subjects participated. 1.1.2 Prevalence Amblyopia is a significant ...
The visual acuity test is used to determine the smallest letters you can read on a standardized chart (Snellen chart) or a card held 20 feet (6 meters) away.
Visual acuity test with Snellen eye chart examination for nursing students. This eye examination checks cranial nerve II, which is the optic nerve. Youll want
TY - JOUR. T1 - eHealth tools for the self-testing of visual acuity. T2 - a scoping review. AU - Yeung, Wai Kent. AU - Dawes, Piers. AU - Pye, Annie. AU - Neil, Malcolm. AU - Aslam, Tariq. AU - Dickinson, Christine AU - Leroi, Iracema. N1 - Copyright the Author(s) 2019. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.. PY - 2019/8/22. Y1 - 2019/8/22. N2 - Uncorrected refractive error is a major cause of vision impairment, and is indexed by visual acuity. Availability of vision assessment is limited in low/middle-income countries and in minority groups in high income countries. eHealth tools offer a solution; two-thirds of the globe own mobile devices. This is a scoping review of the number and quality of tools for self-testing visual acuity. Software applications intended for professional clinical use were excluded. Keyword searches were conducted on Google online, ...
This study will develop estimates of visual acuity outcomes in children with PON 6 months following enrollment.. Secondary Objectives:. To describe visual acuity outcomes at 1 month, 1 year, and 2 years after enrollment.. To estimate the risk of an acute optic neuritis recurrence in the same eye at two years after enrollment.. To estimate the risk of developing acute PON in the fellow eye at two years after enrollment for children with unilateral PON at presentation.. To estimate the risk of diagnosis of MS 2 years after enrollment.. To characterize PON including prevalence of white matter lesions on MRI and neuromyelitis optica (NMO) antibodies at enrollment.. To determine retinal nerve fiber thickness and ganglion cell layer thickness - using spectral domain OCT at 1 month, 6 months, 1 year and 2 years after enrollment.. To collect MRIs for future analyses. To assess quality of life (QOL) outcomes using current pediatric instruments at 6 months.. To describe low contrast visual acuity outcomes ...
We aimed to examine the effect of different doses of lutein supplementation on visual function in subjects with long-term computer display light exposure. Thirty-seven healthy subjects with long-term computer display light exposure ranging in age from 22 to 30 years were randomly assigned to one of three groups: Group L6 (6 mg lutein/d, n 12); Group L12 (12 mg lutein/d, n 13); and Group Placebo (maltodextrin placebo, n 12). Levels of serum lutein and visual performance indices such as visual acuity, contrast sensitivity and glare sensitivity were measured at weeks 0 and 12. After 12-week lutein supplementation, serum lutein concentrations of Groups L6 and L12 increased from 0.356 (SD 0.117) to 0.607 (SD 0.176) mu mol/l, and from 0.328 (SD 0.120) to 0.733 (SD 0.354) mu mol/l, respectively. No statistical changes from baseline were observed in uncorrected visual acuity and best-spectacle corrected visual acuity, whereas there was a trend toward increase in visual acuity in Group L12. Contrast ...
Hintergrund: Die Sehschärfebestimmung ist die am häufigsten geprüfte Sehfunktion. Landoltringe und Buchstaben werden oftmals als Sehzeichen zur Sehschärfebestimmung verwendet. In dieser Studie werden vier Sehtestmetho-den miteinander verglichen, welche derartige Optotypen darbieten: Der Freiburg Visual Acuity Test (FrACT), unter Verwendung eines Nummernblocks (FrACTk), bzw. eines rotierbaren, haptischen Landoltrings (FrACTh) als Eingabegeräte, die Tübingen Landolt Chart, auf welcher Landoltringe nach den Vorgaben der ISO 8596 sowie DIN 58220 Teil 3 dargeboten werden und ETDRS-Sehzeichentafeln. Ziele der Studie waren es (i) den Unterschied zwischen der subjektiven Bewertung der Testmethoden durch Probanden selbst, sowie die Beurteilung des Zurechtkommens der einzelnen Versuchspersonen durch den Untersucher, unter Verwendung von visuellen Analogskalen (VAS) herauszufinden und hinsichtlich der Testdauer (ii) die Ermittlung der Inter-Test Reliabilität zwischen den Methoden und (iii) deren Test-Retest
Visual acuity tests are the most common tests used to evaluate eyesight. They measure the eyes ability to see details at near and far distances. The tests usually involve reading letters or looking at symbols of different sizes on an eye chart.
TY - JOUR. T1 - Visual acuity and pupillary reactions after peribulbar anaesthesia. AU - Talks, S.J.. AU - Chong, N.H.. AU - Gibson, J M. AU - Francis, I.R.. PY - 1994. Y1 - 1994. N2 - The effect of peribulbar anaesthesia on optic nerve function in 20 patients, before and after cataract surgery, was measured. All the patients had decreased visual acuity. Five (25%) had no perception of light. Seventeen (85%) developed a relative afferent pupil defect (RAPD). No patients saw the operating instruments. Seven (35%) had improved visual acuity immediately postoperatively. Patients should be warned that they may lose vision completely on being given a peribulbar anaesthetic; however their vision will improve, but not necessarily immediately, postoperatively. Examination for an RAPD is a good method of providing reassurance that the operating instruments will not be seen.. AB - The effect of peribulbar anaesthesia on optic nerve function in 20 patients, before and after cataract surgery, was measured. ...
Shallo-Hoffmann, Josephine; Coulter, Rachel; Oliver, Pamela; Friedman, S; Hardigan, Patrick; and Blavo, Cyril, A Comparison of Visual Acuity Tests as a Function of Age and Socio-ethnic Group in a Pre-school Vision Screening Study (2002). College of Osteopathic Medicine Faculty Articles. 524 ...
Aim: To evaluate the visual acuity outcomes with ranibizumab (RBZ) according to baseline ischaemic status in patients with macular oedema secondary to branch or central retinal vein occlusion (BRVO and CRVO) Methods: Analysis of 2 multicenter randomized clinical trials (CRUISE and BRIGHTER) Results: Data of 392 CRVO patients randomized in CRUISE and 455 BRVO patients randomized in BRIGHTER were analysed. Best-corrected visual acuity (BCVA) was measured using ETDRS charts at each visit. Presence or absence of retinal ischaemia at baseline was assessed by fluorescein angiography by the central reading centre (CRC). In CRUISE, ischaemia was defined as ,30% total capillary loss in the center subfield by area. In BRIGHTER, ischaemia was defined as present if capillary loss was detected and scored as mild, moderate, severe or complete in at least one location of the center, inner or outer subfields. Baseline visual acuity, and change from baseline were reported according to ischaemic status as a ...
What is visual acuity? Visual acuity is only one in a series of factors that evaluate ones vision.To learn more about visual acuity visit our website for more information. Should you have any questions or concerns please call Stamper Optometry at: 415-824-2374
76 eyes of 38 patients were included in this study. The mean age at surgery was 54 years. The binocular corrected visual acuity averaged -0,1 logMAR for distance vision and +0,06 logMAR for near vision preoperatively. Postoperatively, non corrected binocular visual acuity was -0,1 logMAR for distance vision and +0,36 logMAR for near vision. The spherical equivalent averaged -0,36D on the eye corrected for distance vision. The difference between postoperative binocular uncorrected visual acuity and preoperative binocular best corrected visual acuity was statistically significant for distance vision (p = 0.0072) but not in near vision (p> 0.05). Two eyes requiered retreatment. 33 patients were satisfied or very satisfied with the visual result ...
The study group consists of 8 females and 12 males, with mean age 69.45 ± 10.76 (31-86) years. At 6 months after the surgery the mean spherical equivalent was -0.04 ± 0.12 D in ReZoom implanted eyes and -0.11 ± 0.2 D in Tecnis implanted eyes. The uncorrected distance and intermediate visual acuity levels were significantly better in ReZoom implanted eyes at 6 months after the surgery (p=0.026 and p=0.037,respectively). There was no statistically significant difference in the uncorrected near viasual acuity (p>0.05). At the final visit, the mean binocular uncorrected distance visual acuity was -0.05±0.1 logMAR, the mean binocular uncorrected intemediate visual acuity was 0.1±0.2 logMAR and the mean binocular uncorrected near visual acuity was 0.1±0.1 logMAR. There was no statistically significant difference in contrast sensitivity, reading speed, halos, or glare between the groups ( ...
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There is an unexpected problem, though: Our visual acuity is so high that even at 5 m distance the spatial resolution of computer screens is insufficient to adequately assess acuity (Bach 1996). One could increase observer distance, but that would require huge screens under pathologic conditions. LCD displays currently are worse than cathode ray tubes, and the latter are limited by shadow masks electron optics, so-called high-resolution screen are just bigger, the pixel size is not smaller. But advanced computer graphics provides a solution, the so-called anti-aliasing. This term has been popularized in flyers for CD players and is increasingly used in computer graphics. Spatial resolution is improved with the help of intensity resolution. Optics of the human eye represent a low-pass filter for spatial frequencies, and --after passage through the optics-- an anti-aliased image leads to the same retinal image as an image with veridical higher resolution. The principle is depicted in the ...
Westheimer, G (1 January 1965). "Visual Acuity". Annual Review of Psychology. 16 (1): 359-380. doi:10.1146/ ... Gittings, Neil S.; Fozard, James L. (1986). "Age related changes in visual acuity". Experimental Gerontology. 21 (4-5): 423-433 ... atmospheric aerosols such as dust or air pollution visual acuity of the observer wind (can cause stars to twinkle, and render ... Assuming normal visible acuity and clear skies, it is possible to approximately convert Globe at Night naked eye limiting ...
Visual acuity. A practical measure of binocularity is the binocular summation ratio BSR, which is the ratio of binocular ... By combining the information received in each eye, binocular summation can improve visual acuity, contrast sensitivity, flicker ... Binocular summation refers to the improved visual performance of binocular vision compared to that of monocular vision. The ... Some of the ways in which binocular summation improves binocular visual performance are Brightness perception. The binocularly ...
Their visual acuity may rival some eagles from the genus Aquila and some of the larger falcons as the greatest of all diurnal ... Fox, R., Lehmkuhle, S.W., & Westendorf, D.H. (1976). Falcon visual acuity. Science, 192(4236), 263-265. Chapin, J.P., & Lang, H ... Reymond, L. (1985). Spatial visual acuity of the eagle Aquila audax: a behavioural, optical and anatomical investigation. ... Martial eagles have been noted as remarkable for their extremely keen eyesight (3.0-3.6 times human acuity), partly due to ...
Fox, R; Lehmkuhle, S.; Westendorf, D. (1976). "Falcon visual acuity". Science. 192 (4236): 263-65. doi:10.1126/science.1257767 ... the visual acuity of one species has been measured at 2.6 times that of a normal human. Peregrine falcons have been recorded ...
Low vision is defined as a best-corrected visual acuity worse than 0.5 LogMAR but equal or better than 1.3 LogMAR in the better ... When using a LogMAR chart, visual acuity is scored with reference to the logarithm of the minimum angle of resolution, as the ... Blindness is defined as a best-corrected visual acuity worse than 1.3 LogMAR. Bailey IL, Lovie JE. I (1976.) New design ... CS1 maint: discouraged parameter (link) Bailey IL, Lovie JE (2013). Visual acuity testing. From the laboratory to the clinic. ...
Her most notable work was in the area of visual acuity testing where she developed and improved equipment. Sloan received her ... Sloan's lifetime of work in the area of visual acuity testing continues to have many longstanding applications to the work done ... Sloan, Louise L. (1959-12-01). "New test Charts for the Measurement of Visual Acuity at far and Near Distances*". American ... Bailey, Ian L.; Lovie-Kitchin, Jan E. (2013-09-20). "Visual acuity testing. From the laboratory to the clinic". Vision Research ...
... decreased visual acuity; seeing specks or spots; teary eyes; or eye discharge or crusting. On February 25, 2005, Alcon filed a ...
Land MF (1997). "Visual acuity in insects". Annual Review of Entomology. 42: 147-77. doi:10.1146/annurev.ento.42.1.147. PMID ... This visual arrangement is known as neural superposition. Since an image from the compound eye is created from the independent ... The advantage of this arrangement is that the same visual axis is sampled from a larger area of the eye, thereby increasing ... and each rhabdomere is united with those from the six adjacent ommatidia that share the same visual axis. Thus, at the level of ...
Land, Michael F. (January 1997). "Visual Acuity in Insects". Annual Review of Entomology. 42 (1): 147-177. doi:10.1146/annurev. ... "The visual orientation strategies of Mantis religiosa and Empusa fasciata reflect differences in the structure of their visual ... The overlap of the visual field of the two eyes is 40° in nymphs and up to 70° in adults. The pseudopupil, a small, dark region ... The development of the visual system was reviewed by Karl Kral in 2014: while high-contrast cues could be perceived by adults ...
Westheimer, G. (1975). Visual acuity and hyperacuity. Investigative Ophthalmolology, 14, 570-572. Gilbert, C., Ito, M., Kapadia ... M., & Westheimer, G. (2000 ). Interactions between attention, context and learning in primary visual cortex. Vision Research, ...
following G. Westheimer Westheimer, Gerald (1975). "Visual acuity and hyperacuity". Investigative Ophthalmology and Visual ... a spatial resolution in certain visual tasks that exceeds visual acuity by about an order of magnitude. In his famous 1899 ... Strasburger, Hans; Huber, Jörg; Rose, David (2018). "Ewald Hering (1899) On the Limits of Visual Acuity: A Translation and ... On the Limits of Visual Acuity. [Ueber die Grenzen der Sehschärfe] (1899/2018) Outlines of a Theory of the Light Sense [ ...
Westheimer, G. (1975-08-01). "Editorial: Visual acuity and hyperacuity". Investigative Ophthalmology & Visual Science. 14 (8): ... Visual acuity is measured by the smallest letters that can be distinguished on a chart and is governed by the anatomical ... This defines the resolution limit and the basis of visual acuity. A quite different mechanism operates in hyperacuity, whose ... Strasburger, Hans; Huber, Jörg; Rose, David (2018). "Ewald Hering (1899) On the Limits of Visual Acuity: A Translation and ...
Visual acuity is slightly reduced. Granular corneal dystrophy is caused by a mutation in the TGFBI gene, located on chromosome ...
Primary visual factors: Quantitative: Decreased visual acuity (myopia, hyperopia, astigmatism) Qualitative: Irregular ... After the glass was removed by this method and the cornea healed, Fyodorov found that the boy's visual acuity had improved ... Symons SP, Slomovic AR (August 1994). "Visual acuity, refractive and keratometric results of 140 consecutive radial keratotomy ... Visual acuity is generally improved. The healing corneal wounds consist of newly abutting corneal stroma, fibroblastic cells, ...
Visual hyperacuity is at least 10 times more sensitive than visual acuity, the ability to separate between distinct objects. ... PHP takes advantage of visual hyperacuity, also known as vernier acuity-the ability to identify the misalignment of visual ... Westheimer G. (August 1975). ""Editorial: Visual acuity and hyperacuity"". Invest Ophthalmol. 14 (8): 570-572. PMID 1150397.. ... Another problem is that minute visual aberrations can be normal and therefore should be distinguished from genuine visual ...
2 Visual Acuity, Contrast Sensitivity". University of Utah. Retrieved 19 July 2009.. ... In the study of visual perception, sinusoidal gratings are frequently used to probe the capabilities of the visual system. In ... The spatial-frequency theory refers to the theory that the visual cortex operates on a code of spatial frequency, not on the ... Most neurons in the primary visual cortex respond best when a sine-wave grating of a particular frequency is presented at a ...
A horse has higher acuity through most of the visual field of its eyes than a human has, but does not match the high acuity of ... is then the measurement of visual acuity of the eye. For a human eye with excellent acuity, the maximum theoretical resolution ... Visual acuity, or resolving power, is "the ability to distinguish fine detail" and is the property of cone cells. It is often ... For example, the eye of a bird of prey has much greater visual acuity than a human eye, and in some cases can detect ...
... has superhuman visual acuity. He possesses an above normal intellect, with a capacity for unlimited self-motivated ... as he experienced visual hallucinations (?) of a miniature Celestial helping him overcome his psychological issues.[volume & ... A Visual History. DK Publishing. pp. 185, 219. ISBN 978-1465455505. Markstein, Don. "Machine Man". Don Markstein's Toonopedia. ...
He also possessed superhuman visual acuity. Skurge was extremely long-lived, aging at a much slower pace than human beings, ... Brevoort, Tom; DeFalco, Tom; Manning, Matthew K.; Sanderson, Peter; Wiacek, Win (2017). Marvel Year By Year: A Visual History. ...
However, some visual abnormalities can remain even where visual acuity is measured at 20/20. Lasting problems include decreased ... Reduced visual acuity may persist after the fluid has disappeared. The disease is considered of unknown cause. It mostly ... Recovery of visual acuity usually follows. Treatment should be considered if resorption does not occur within 3-4 months, ... It would appear that the presence of the bacteria is well correlated with visual acuity and other retinal findings following an ...
Yonemitsu F., Sung Y., Naka K., Yamada Y. and Marmolejo-Ramos F. (2017). «Does weight lifting improve visual acuity? A ... For example, the visual field, which shows concentric reduction, increased up to 5 times in the most acute case, and the image ... It consists of two volumes, the first one published in 1945 focused on visual functions and the second one published in 1950 ... Gonzalo-Fonrodona, I.; Porras, M.A. (2007). «Physiological Laws of Sensory Visual System in Relation to Scaling Power Laws in ...
A research experiment done in the UK in 1968 using tungsten (non-halogen) lamps found that visual acuity is about 3% better ... Cite journal requires ,journal= (help) Christie, A.W.; Ashwood, J.E.; Symons, R.D.H. (1968). "Visual Acuity in Yellow ... though the effect of this reduction is said to be mitigated or countervailed by the increased visual acuity available with ... These wavelengths are difficult for the human visual system to process properly, and they cause perceived dazzle and glare ...
Franciscus Donders introduces the term visual acuity. Guillaume Duchenne describes Duchenne muscular dystrophy. Prosper Ménière ...
Individuals with MORM syndrome experience decreased visual acuity, meaning their ability to see distinct sharp lines decreases ... CS1 maint: discouraged parameter (link) "Visual Acuity". American Optometric Association. Retrieved 3 December 2015. CS1 maint ... Any further reduction in vision acuity is not observed until the individual is between the ages thirty to forty. Delayed ...
Visual acuity is more or less normal. Lattice dystrophy starts as fine branching linear opacities in Bowman's layer in the ... Visual acuity eventually becomes reduced during the second and third decades of life following a progressive superficial haze ... generalized corneal edema and decreased visual acuity. In advanced cases, abnormalities are found in the all layers of the ... Some cause severe visual impairment, while a few cause no vision problems and are diagnosed during a specialized eye ...
Gagnon, Yakir L.; Sutton, Tracey T.; Johnsen, Sönke (November 2013). "Visual acuity in pelagic fishes and mollusks". Vision ...
Loss of visual acuity may start with a blur or haze at the point of fixation, followed by a progressive decline. The degree of ... Visual acuity usually recovers before color vision. In industrialized nations, toxic and nutritional optic neuropathy is ... Toxic and nutritional optic neuropathy is a group of medical disorders defined by visual impairment due to optic nerve damage ... Peripheral vision is usually spared since the pattern of loss typically involves a central or cecocentral scotoma, a visual ...
Visual acuity transiently deteriorates during the attack. Older patients may show faint to definite central, horizontally oval ... The opacities may be associated with decreased visual acuity, but they have not been severe enough to need corneal ... The repeated corneal inflammation over time can lead to reduced visual acuity. Keratoendotheliitis fugax hereditaria was first ...
Intermittent control Craik, K. J. W. (January 1939). "The effect of adaptation upon visual acuity". British Journal of ...
"Human visual ecology and orientation anisotropies in acuity." Science 182, no. 4113 (1973): 729-731. Nelson, J. I., and B. J. ... "Orientation-selective inhibition from beyond the classic visual receptive field." Brain Research 139, no. 2 (1978): 359-365. ...
... and is the region capable of producing the highest visual acuity or highest resolution. Across the rest of the retina, rods and ... each contributing information used by the visual system to form a representation of the visual world, sight. The rods are ... Rods are extremely sensitive, and can be triggered by a single photon.[3][4] At very low light levels, visual experience is ... Closest to the visual field (and farthest from the brain) is the axon terminal, which releases a neurotransmitter called ...
... producing a slight increase in contrast and visual acuity. Antireflective ophthalmic lenses should not be confused with ...
Central visual acuity of 20/200 or less in the better eye with corrective glasses or central visual acuity of more than 20/200 ... Visual impairments may take many forms and be of varying degrees. Visual acuity alone is not always a good predictor of the ... Defined as having central visual acuity of less than 3/60 with normal fields of vision, or gross visual field restriction. ... Visual impairment is often defined as a best corrected visual acuity of worse than either 20/40 or 20/60.[5] The term blindness ...
... s found in areas of the body with less tactile acuity tend to have larger receptive fields. ... Visual system (sense of vision). *Auditory system (sense of hearing). *Vestibular system (sense of balance) ...
They found no lasting decrease in visual acuity.[7] The European Parliament Scientific and Technological Options Assessment ( ... The Journal of Investigative Ophthalmology and Visual Science published a study that concluded that single exposure of the eye ... 41 (8): 2138 - Investigative Ophthalmology & Visual Science". Retrieved 2011-12-02.. ...
He did research on astigmatism, glaucoma and other eye diseases as well as research on correction of visual acuity using ... "How Visual Acuity Is Measured", Macular Degeneration Support, October 2003. Accessed July 6, 2010. ... to measure visual acuity, which rapidly become the global standard.[3] The most significant innovation was his use of what he ... was a Dutch ophthalmologist who introduced the Snellen chart to study visual acuity (1862). He took over directorship of the ...
Visual acuity is more or less normal. Lattice dystrophy starts as fine branching linear opacities in Bowman's layer in the ... Visual acuity eventually becomes reduced during the second and third decades of life following a progressive superficial haze ... generalized corneal edema and decreased visual acuity. In advanced cases, abnormalities are found in the all layers of the ... Some cause severe visual impairment, while a few cause no vision problems and are diagnosed during a specialized eye ...
... efficacy endpoint for the study was denoted by the proportion of the patients who lost less than 15 letters of visual acuity ...
In the CNS for example, cranial nerve injury typically presents as a visual acuity loss 1-14 years post treatment.[25] In the ...
Serious disability is equivalent to visual acuity of less than 20/200 Snellen measured using both eyes. ...
... while the accompanying visual acuity is insufficient for such activities. Furthermore, this limited acuity is matched by a low ... suggesting that the visual midbrain plays a more important role than the visual cortex, as in some rodents. These features ... developing its electrosensory system at the cost of its visual system; an evolutionary process paralleled by the small number ...
However, the pupils should be normally reactive, and the visual acuity normal. ... If visual loss, significant pain, sensitivity to light, signs of herpes, or if symptoms do not improve after a week, further ...
... megabats have a well-developed visual cortex and good visual acuity.[34] Megabats have a claw on the second finger of the ... The eyes of most microbat species are small and poorly developed, leading to poor visual acuity, but no species is blind.[92] ... Martini, Frederic (2015). Visual anatomy & physiology. Pearson. pp. 704-705. ISBN 978-0-321-91874-1. . OCLC 857980151.. ...
... diminished visual acuity or blindness, anaphylactic shock, and disturbances in heart rhythm or conduction, and death from ... Attempted suicide by intake of a large dose of quinine has caused irreversible tunnel vision and very severe visual impairment. ...
... such as visual acuities, contrast sensitivity, fundus auto-fluorescence (FAF), dark-adapted visual thresholds, vascular ... The methods used varied among the three trials, but included both functional methods such as visual acuity[65][66][67] and ... See also: Adaptation (eye) and Visual acuity. The retina translates an optical image into neural impulses starting with the ... Despite occupying about 0.01% of the visual field (less than 2° of visual angle), about 10% of axons in the optic nerve are ...
The lower line of text simulates the acuity of vision with the relative acuity percentages. The difficulty of recognizing text ... Eye movement in reading involves the visual processing of written text. This was described by the French ophthalmologist Louis ... Salvucci, D.D. (2001). An integrated model of eye movements and visual encoding. Cognitive Systems Research, 1(4), 201-220. ... Liu, Y.; Zhou, Z.; Hu, D. (2011). "Gaze independent brain-computer speller with covert visual search tasks". Clinical ...
Gianfranceschi, L (1999). "Behavioral visual acuity of wild type and bcl2 transgenic mouse". Vision Research Journal. 39: 569- ... doi:10.1016/s0301-0082(03)00051-0. Finlay, BL (1989). "Control of cell number in the developing mammalian visual system". ... Visual Science. 39: 1713-1720. White, FA (1998). "Widespread elimination of naturally occurring neuronal death in Bax-deficient ...
둘째, visual acuity test에서, 대조군(망막색소상피세포 미처리군)에 비하여, 실험군(망막색소상피세포 처리군)에서 중심시야(general vision)과 주변시야(peripheral vision)가 증가함을 통하여 ... 시각회로 조절(visual cycle)[편집]. 망막색소상피세포는 광 변환(phototransduction)을 통한 외부 시각 회로의 작용을 일정하게 유지하는 역할을 한다. 광변환은 망막에 존재하는 광수용세포의 광색소( ... 광수용(light absorption), 물질 수송(epithelial transport), 시각회로 조절(visual cycle), 식세포작용(phagocytosiss), 호르몬 분비 및 면역조절 작용 등을 수행한다. ... Strauss, O (2005). "The Retinal Pigment Epithelium in Visual Function". 》Physiological review》 85 (3): 845-881. PMID 15987797. ...
Distant and near visual acuity: Must be correctable to 20/20, each eye separately (corrective lenses such as glasses are ...
If the papilledema has been longstanding, visual fields may be constricted and visual acuity may be decreased. Visual field ... Longstanding papilledema leads to optic atrophy, in which the disc looks pale and visual loss tends to be advanced.[5][9] ... The primary goal in treatment of IIH is the prevention of visual loss and blindness, as well as symptom control.[9] IIH is ... Long-term untreated papilledema leads to visual loss, initially in the periphery but progressively towards the center of vision ...
... reduced visual acuity, and myopia (nearsightedness).[24] Visual acuity usually falls to the 20/50 to 20/400 range. ... When the need to process visual information as rapidly as possible arises, for example in an emergency situation, the visual ... may also have decreased visual acuity and be uncomfortable in bright environments.[2] ... Webvision: The Organization of the Retina and Visual System. PMID 21413396. Archived from the original on May 9, 2018.. ...
Melanin in the pigment epithelium is critical for visual acuity and contrast. Loss of melanogenesis function is linked to the ...
McKenna's hypothesis was that low doses of psilocybin improve visual acuity, meaning that the presence of psilocybin in the ... His ideas regarding psilocybin and visual acuity have been criticized by suggesting he misrepresented Fischer et al., who ... Criticism has also been expressed due to the fact that in a separate study on psilocybin induced transformation of visual space ... published studies about visual perception in terms of various specific parameters, not acuity. ...
There is a pronounced tendency for there to be a trade-off between visual acuity and chemical or tactile acuity, such that most ... Möller, R. (2002). A Biorobotics Approach to the Study of Insect Visual Homing Strategies (PDF) (in German). p. 11.. ...
Bruce, V.; Green, P.; Georgeson, M. (1996). Visual perception: Physiology, psychology and ecology (3rd ed.). LEA. p. 110.. ... A frog hunts on land by vision... He has no fovea, or region of greatest acuity in vision, upon which he must center a part of ... Lettvin, J.Y., Maturana, H.R., Pitts, W.H., and McCulloch, W.S. (1961). Two Remarks on the Visual System of the Frog. In ... Experiments using the visual sensory modality found that movement of elements of an object produce paths that individuals ...
In 1 to 3% of cases, loss of best corrected visual acuity (BCVA) can result, due to decentered ablative zones or other surgical ... A 2017 systematic review found uncertainty in visual acuity, but found that in one study, those receiving PRK were less likely ... Most modern lasers will automatically center on the patient's visual axis and will pause if the eye moves out of range and then ... Visual outcomes and adverse effects". Lasers in surgery and medicine. 44 (6): 475-81. doi:10.1002/lsm.22036. PMID 22674627.. ...
Passive visual warningsEdit. A South Western Ambulance Service ambulance displays reversed wording and the Star of Life, with ... "Implementation Guidelines for the Canadian ED Triage & Acuity Scale (CTAS). Canadian Association of Emergency Physician. ... The active visual warnings are usually in the form of flashing lights. These flash in order to attract the attention of other ... The passive visual warnings are usually part of the design of the vehicle, and involve the use of high contrast patterns. Older ...
Although the numbat finds termite mounds primarily using scent, it has the highest visual acuity of any marsupial, and, ...
They include the visual and tactile placing reflexes.[30]. Learning new skillsEdit. Proprioception is what allows someone to ... Goble, DJ (2010). "Proprioceptive acuity assessment via joint position matching: From basic science to general practice". ... without the aid of visual or vestibular information.[35] During such tasks, individuals are blindfolded while a joint is moved ... that the brain retains a memory of specific limb positions and that after amputation there is a conflict between the visual ...
... visual acuity. Thus, "normal" visual acuity by no means implies normal vision. The reason visual acuity is very widely used is ... Visual acuity alone thus cannot determine the overall quality of visual function. Visual acuity is a measure of the spatial ... Bach M (2016). "The Freiburg Visual Acuity Test". Visual Functions Committee (25 May 1984). "Visual acuity measurement standard ... So, distant visual acuity of 6/10 and 6/8 with pinhole in the right eye will be: DscOD 6/10 PH 6/8. Distant visual acuity of ...
The visual acuity test is used to determine the smallest letters you can read on a standardized chart (Snellen chart) or a card ... Visual acuity is expressed as a fraction.. *The top number refers to the distance you stand from the chart. This is often 20 ... The visual acuity test is used to determine the smallest letters you can read on a standardized chart (Snellen chart) or a card ... The visual acuity test is a routine part of an eye examination or general physical examination, particularly if there is a ...
To simulate the loss of visual acuity we introduce a novel diffusion Partial Differential Equation (PDE) which takes luminance ... We use a set of very simple equations, based on real physical data and visual perception experimental data. ... Keywords: Day for night, visual perception, dark adaptation, Webers Law, non-linear diffusion 1. ... ARTICLE{Haro_visualacuity,. author = {Gloria Haro and Marcelo Bertalmío},. title = {Visual acuity in day for night},. journal ...
Visual acuity tests may be performed in many different ways. It is a quick way to detect vision problems and is frequently used ... Visual acuity tests may be performed in many different ways. It is a quick way to detect vision problems and is frequently used ...
... the commonest side effect is a residual refractive error and poor uncorrected visual acuity (UCVA). In this work, we aim at ...
Visual Acuity sets the bar with dynamic spatial rendering applied to starbursting synths and rogue Garage patterns, while You ... Visual Acuity sets the bar with dynamic spatial rendering applied to starbursting synths and rogue Garage patterns, while You ... Visual Acuity sets the bar with dynamic spatial rendering applied to starbursting synths and rogue Garage patterns, while You ... Visual Acuity sets the bar with dynamic spatial rendering applied to starbursting synths and rogue Garage patterns, while You ...
... , Vision Screening, Snellen Chart, ETDRS Visual Acuity Chart, Rosenbaum Chart, HOTV Card. ... Acuities, Visual, Acuity, Visual, Visual Acuities, visual acuity, acuity visual, Visual Acuity, Visual acuity, function ( ... Visual Acuity. Visual Acuity Aka: Visual Acuity, Vision Screening, Snellen Chart, ETDRS Visual Acuity Chart, Rosenbaum Chart, ... CHART, VISUAL ACUITY, Visual acuity chart (physical object), Visual acuity chart, Charts, Eye, Visual Acuity, Snellen Eye ...
... , Vision Screening, Snellen Chart, ETDRS Visual Acuity Chart, Rosenbaum Chart, HOTV Card. ... Visual Acuity is THE Vital Sign of the eye. *Obtain Visual Acuity on all patients with eye complaints ... Visual Acuity, Vision Screening, Snellen Chart, ETDRS Visual Acuity Chart, Rosenbaum Chart, HOTV Card ... In acute eye complaints, perform Visual Acuity with their vision correction (e.g. glasses) ...
Visual Acuity Test + Glasses Checker. ,b,Free Visual Acuity test,/b, that will help you detect problems... ... Visual Acuity Test: Free Android app (4.4 ★, 500,000+ downloads) → ... The Visual acuity test features: • Visual Acuity Test. Snellen eye test, LogMAR chart, Golovin-Sivtsev table, Landolt C / ... The Visual acuity test features: • Visual Acuity Test. Snellen eye test, LogMAR chart, Golovin-Sivtsev table, Landolt C / ...
Download Visual Acuity Test for Android to measurement app that records the results of the standard visual acuity test and ... Measurement app that records the results of the standard visual acuity test and intraocular pressure test. ...
Background: There is a paucity of systematically collected data on visual impairment in patients with chronic psychiatric ... Ungvari, G., Tang, W., Wong, W. et al. Distant visual acuity in chronic psychiatric patients. Soc Psychiatry Psychiatr ... The aim of this pilot study was to estimate the magnitude of impairment of distant visual acuity (DVA) including refractive and ... Key words myopia - distant visual acuity - antipsychotic drugs - rehabilitation - deinstitutionalization - chronic psychiatric ...
Visual acuity was assessed with the aid of a Snellen chart.. RESULTS: Nearly 6% of the survey group had visual acuity worse ... A survey of the visual acuity of Brisbane drivers.. McConnell RA1, Spall AD, Hirst LW, Williams G. ... Many licence holders do not meet the present visual acuity criteria of the Queensland Department of Transport. ... To conduct a survey of the visual acuity of a group of Brisbane Drivers. ...
Visual acuity; the ability of the eye to perceive the shape of objects in the direct line of sight. Visual acuity is measured ... Visual acuity notation; ability to see at 20 feet what others with normal acuity are able to see at 70 feet. Visually impaired. ... Visual acuity notation; ability to see at 20 feet what others with normal acuity are able to see at 200 feet. Legally blind. ... Normal visual acuity; ability to correctly perceive an object or letter of a designated size from a distance of 20 feet. ...
Copyright ® 2018 all rights reserved by Organic Authority, Inc, and can not be reproduced without permission in writing. We are a digital magazine for entertainment, we are not here to diagnose or treat any health or medical conditions. When making any health or lifestyle changes consult your primary care physician.. ...
Controversy surrounds the averaging of visual acuity scores. We examine this debate and provide a series of guidelines and ... Visual acuity: calculating appropriate averages Acta Ophthalmol (Copenh). 1993 Jun;71(3):296-300. doi: 10.1111/j.1755-3768.1993 ... Controversy surrounds the averaging of visual acuity scores. We examine this debate and provide a series of guidelines and ...
Brightness acuity test and outdoor visual acuity in cataract patients.. Holladay JT, Prager TC, Trujillo J, Ruiz RS. ... There was no decrease in visual acuity in the 14 normal patients, but there was a one to ten line decrease in vision among the ... A simple device, the brightness acuity tester (B.A.T.), was developed to predict a patients functional outdoor acuity. The B.A ... The disparity between functional outdoor vision and the acuity measured in the standard refracting lane is well known among ...
Eye Visual acuity Orthostatic hypotension Orthostatic hypertension Blood pressure variability End-organ damage ... Hodos W, Miller RF, Ghim MM, Fitzgerald ME, Toledo C, Reiner A (1998) Visual acuity losses in pigeons with lesions of the ... Visual acuity (VA) was assessed using the Early Treatment Diabetic Retinopathy Study (EDTRS) LogMAR chart. The relationship ... Colenbrander A (2002) Visual standards, aspects and range of vision loss with emphasis on population surveys. Report prepared ...
Compositions and methods for enhancing visual acuity in animals are disclosed. The compositions and methods utilize long chain ... The term "visual acuity" or "visual performance" are used interchangeably herein, and refer to the eyes ability to resolve ... "Enhanced visual acuity" refers to any improvement in the eyes ability to resolve fine details or small distances, as measured ... A method for enhancing visual acuity in an animal comprising administering to the animal one or more LCPUFA in an amount ...
Recommended Practices Recommendation Summary Visual acuity is the quantifiable measure of the ability to iden ... Ideally, tests of visual acuity should have the same number of optotypes for each acuity level and the same proportional ... Visual acuity is the quantifiable measure of the ability to identify black symbols on a white background at a standardized test ... For visual acuity testing, appropriately scaled (logMAR) single crowded HOTV letters or Lea symbols surrounded by crowding bars ...
Treatments and Tools for Visual acuity test. Find Visual acuity test information, treatments for Visual acuity test and Visual ... MedHelps Visual acuity test Center for Information, Symptoms, Resources, ... The visual acuity of my left eye has reduced to 6/18. Can u please tell me an... ... I am a stucent of MBBS 2nd year.My visual acuity has decreased to 6/24. Can i increase my v... ...
The visual acuity of the eye is an important measure of its ability to function well. 2.1 Visual Acuity Standard visual acuity ... 6/5 acuity is better than 6/6 acuity, and 6/9 acuity is worse than 6/6 acuity. Although 6/6 is normal visual acuity for most ... Visual acuity is also defined as the reciprocal of the visual angle expressed in minutes of arc. Acuity is said to be normal if ... 3.1 Visual Acuity Measurements Visual acuity measurements of the participants were carried out using the Snellen letters. The ...
The Snellen Eye Chart is used to test visual acuity. This test measures how well you see at various distances. Shop & Save! ... Visual Acuity Eye Charts. Snellen Eye Chart. The Snellen Eye Chart is used to test visual acuity, position the patient 10 or 20 ... who came up with them as a test of visual acuity. Visual acuity refers to the clarity or clearness of the vision, a measure of ... Snellen Eye Chart - Visual Acuity Eye Charts is also listed in these categories:. / Diagnostic Products. / ,a href=/diagnostic ...
... All you need to do is prove to your customer(s) that any one of your inspectors ... Re: UV/ White Light Conditions- Visual Acuity : When testing with MPI, the background light problem. : can be solved by using ... Re: UV/ White Light Conditions- Visual Acuity When testing with MPI, the background light problem. can be solved by using ... UV/ White Light Conditions- Visual Acuity Hello NDTers. I would be interested to know if anybody knows of any documented ...
Missing a single ophthalmology appointment over a two-year period was associated with decreased visual acuity for patients with ... Missing doctors visit linked to decreased visual acuity for patients with AMD. *Download PDF Copy ... In fact, each missed visit was associated with an average visual acuity letter score decline of 0.7. Compared to those who ... Ramakrishnan, M.S., et al. (2020) Association of Visit Adherence and Visual Acuity in Patients With Neovascular Age-Related ...
... The procedure is easy to perform, is cost-effective and does ... Pinhole vision has always served as a benchmark for judgment of maximum level of visual acuity that can be attained in a ... Pinhole vision has always served as a benchmark for judgment of maximum level of visual acuity that can be attained in a ... Preoperative image: RK case with a glued IOL, uncorrected visual acuity of 6/60 and astigmatism of 6 D (a). Postoperative image ...
Learning-related visual disabilities include, but are not limited to, the following disorders; ocular motility dysfunction/eye ... A clear statement of the learning-related visual disability with supporting numerical description (the age of acceptable ... visual sensory disorders, and motor integration. Professionals conducting assessment and rendering diagnoses of these ... that might be helpful in understanding the students profile including the use of corrective lenses and ongoing visual therapy ...
This paper intoduces new principles for the design and use of letter charts for the measurement of visual acuity. It is ... or when it is necessary to validate visual acuity scores or detect malingering. Adjusting the visual acuity score according to ... New design principles for visual acuity letter charts Am J Optom Physiol Opt. 1976 Nov;53(11):740-5. doi: 10.1097/00006324- ... This paper intoduces new principles for the design and use of letter charts for the measurement of visual acuity. It is ...
Childrens auditory and visual senses are stimulated when playing with this toy. The activity center can be used independently ...
Visual Acuity is a unique proposition providing experience based independent analysis, design and recommendation based on many ... Visual Acuity is a unique proposition providing experience based independent analysis, design and recommendation based on many ...
  • Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. (
  • 20/20 vision is a term used to express normal visual acuity (the clarity or sharpness of vision) measured at a distance of 20 feet. (
  • For example, using the Snellen fraction with English units, 20/20 or 20/100 indicates that the person being evaluated can see at 20 ft what a person with "normal visual acuity" can see at 20 ft or at 100 ft, respectively. (
  • Representation of the normal visual acuity in a healthy eye. (
  • Visual acuity (VA) was assessed using the Early Treatment Diabetic Retinopathy Study (EDTRS) LogMAR chart. (
  • Ideally, tests of visual acuity should have the same number of optotypes for each acuity level and the same proportional decrease in size from one acuity level to the next smaller level in logMAR progression. (
  • For visual acuity testing, appropriately scaled (logMAR) single crowded HOTV letters or Lea symbols surrounded by crowding bars at a 5-foot (1.5 meter) test distance with the child matching or reading the optotypes aloud should be used. (
  • At 12 months, 18 percent of patients had visual acuity worse than logMAR 0.4 compared with 32 percent at baseline. (
  • Recognition linear acuities were measured with a linear Bailey-Lovie logMAR chart and compared with the sweep VEP estimates. (
  • CONCLUSION: A loss of recognition acuity in the fellow phakic eye of patients treated for unilateral congenital cataract has been demonstrated with a logMAR chart. (
  • Results Experiment 1: The mean age of participants in the adult study was 28.47±7.93 yrs and their mean uncorrected logMAR acuity was 0.9±0.2. (
  • logarithm of the minimum angle of resolution (logMar) ideal is 0.0 and represents 20/20 Snellen acuity. (
  • Validation study (adults): A series of acuity cards with logarithmic progression in spacing and size (1.3 to -0.1 logMAR) designed for a 60 cm test distance was created. (
  • ResultsThe logMAR (Snellen) visual acuity (meanSD) improved significantly with DexNP from 0.41 +/- 0.3 (Snellen 0.39) to 0.32 +/- 0.25 (0.48) and 0.30 +/- 0.26 (0.50) at 4 and 8weeks, respectively. (
  • To simulate the loss of visual acuity we introduce a novel diffusion Partial Differential Equation (PDE) which takes luminance into account and respects contrast, produces no ringing, is stable, very easy to implement and fast. (
  • The USPSTF found adequate evidence that early treatment of refractive error, cataracts, and AMD improves or prevents loss of visual acuity. (
  • Loss of visual acuity in one eye refers to the loss of sharp, clear vision in one eye. (
  • See detailed information below for a list of 14 causes of Loss of visual acuity in one eye , Symptom Checker , including diseases and drug side effect causes. (
  • The following medical conditions are some of the possible causes of Loss of visual acuity in one eye. (
  • Listed below are some combinations of symptoms associated with Loss of visual acuity in one eye, as listed in our database. (
  • Read more about causes and Loss of visual acuity in one eye deaths . (
  • This information refers to the general prevalence and incidence of these diseases, not to how likely they are to be the actual cause of Loss of visual acuity in one eye. (
  • The following list of conditions have ' Loss of visual acuity in one eye ' or similar listed as a symptom in our database. (
  • Eligibility criteria included an age of 18 years or older, best-corrected visual acuity scores between 24 and 78 Early Treatment Diabetic Retinopathy Study letters (20/32 to 20/320 Snellen equivalent), and the presence of DME because of type 1 or 2 diabetes mellitus with a central subfield thickness of greater than 250 µm measured by time-domain optical coherence tomography. (
  • Bevacizumab injections were repeated at months two, three, four, six, seven, eight, 10 and 11 when the central subfield thickness was greater than 250 µm and the Early Treatment Diabetic Retinopathy Study visual acuity score was less than 80 letters (20/25 Snellen equivalent). (
  • While some may argue that the Early Treatment Diabetic Retinopathy Study (ETDRS) chart has revolutionised and standardised VA testing, one could wonder whether the ETDRS VA test methodology has more in common with a computerised visual field test or Goldmann perimetry. (
  • The authors also comment about the rate of decline in letters per year on Early Treatment Diabetic Retinopathy Study (ETDRS) distance acuity testing. (
  • Another common impairment, amblyopia, is caused by the visual brain not having developed properly in early childhood. (
  • There is a paucity of systematically collected data on visual impairment in patients with chronic psychiatric disorders. (
  • The aim of this pilot study was to estimate the magnitude of impairment of distant visual acuity (DVA) including refractive and non-refractive errors in institutionalized psychiatric patients awaiting resettlement in the community in Hong Kong. (
  • Visual impairment can have an adverse effect on an individual's social life, economic status and emotional well-being. (
  • Older age is an important risk factor for most types of visual impairment. (
  • A visual acuity test (such as the Snellen eye chart) is the usual method for screening for visual acuity impairment in the primary care setting. (
  • Impairment of visual acuity is a serious public health problem in older adults. (
  • The acuities of aphakic and fellow phakic eye were compared with the monocular acuities of similarly aged children who have good binocular vision, and with children with severe untreated uniocular visual impairment. (
  • This loss was not apparent in children who have severe untreated uniocular visual impairment and may therefore be an iatrogenic effect of occlusion. (
  • There is inadequate direct evidence that screening and early interventions for impairment of visual acuity by primary care physicians improve functional outcomes in older adults. (
  • Visual Impairment in Children due to Damage to the Brain: Clinics in Developmental Medicine. (
  • Visual acuity measured in this way is called Vernier acuity (a type of hyperacuity) and the discontinuity is specified in terms of its angular size (figure 7). (
  • Missing a single ophthalmology appointment over a two-year period was associated with decreased visual acuity for patients with macular degeneration -- a leading cause of permanent vision loss in the elderly -- according to a new Penn Medicine study. (
  • Sonia Gholami, Nicolaas J. Reus, and Thomas J. T. P. van den Berg, "Changes in Intraocular Straylight and Visual Acuity with Age in Cataracts of Different Morphologies," Journal of Ophthalmology , vol. 2017, Article ID 5649532, 12 pages, 2017. (
  • Investigative Ophthalmology & Visual Science December 1980, Vol.19, 1498-1505. (
  • Pinakin Davey, DO, PhD, professor and director of research at Western University, helped author a study presented at the 2019 Annual Meeting of the Association for Research in Vision and Ophthalmology that explored the reliability of testing methodologies for measuring visual acuity and contrast sensitivity. (
  • We reviewed the records of 27 infants with abnormal eye examinations and visual-evoked response (VER) testing (mean age, 10.5 months) who subsequently underwent a long-term follow-up ophthalmology examination (mean duration, 41 months). (
  • Investigative Ophthalmology & Visual Science June 2017, Vol.58, 5714. (
  • HealthDay News) - Avastin (bevacizumab) and Lucentis (ranibizumab) have similar effects on visual acuity in age-related macular degeneration (AMD), according to a study published online May 2 in Ophthalmology . (
  • The majority of children attending ophthalmology clinics require a visual acuity assessment. (
  • Investigative Ophthalmology and Visual Science. (
  • Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal image within the eye, (2) the health and functioning of the retina, and (3) the sensitivity of the interpretative faculty of the brain. (
  • A common cause of low visual acuity is refractive error (ametropia), errors in how the light is refracted in the eyeball, and errors in how the retinal image is interpreted by the brain. (
  • retinal development using electroretinogram (ERG) and visual processing at the level of the primary visual cortex. (
  • The researchers measured outcomes using retinal photographs from baseline and final visits with data on deterioration of visual acuity. (
  • The results of a measurement of the retinal visual acuity of more than two hundred patients with various types of cataract before extraction of the crystalline lens and after replacement and the determination of the corresponding correction coefficient, reaching 0.7-0.9, make it possible to use the laser retinometer for pre-operative diagnosis. (
  • The purpose of this study was to investigate in the same mouse the long-term effects of chronic exposure to an EE and assess the outcome of this manipulation on cone survival, inner retinal preservation, and visual behavior. (
  • Then, retinal preservation was assessed with immunocytochemistry, confocal microscopy examination, cone counts, and electron microscopy of the photoreceptor layer, while visual acuity was tested behaviorally with a Prusky water maze. (
  • Because the disalignments are often much smaller than the diameter and spacing of retinal receptors, vernier acuity requires neural processing and "pooling" to detect it. (
  • While 99% of such surgeries are successful, the commonest side effect is a residual refractive error and poor uncorrected visual acuity (UCVA). (
  • Pinhole vision has always served as a benchmark for judgment of maximum level of visual acuity that can be attained in a patient with refractive error in the outpatient department. (
  • Apart from these limitations, a number of factors also affect visual acuity such as refractive error, illumination, contrast and the location of the retina being stimulated. (
  • The USPSTF found convincing evidence that screening with a visual acuity test can identify persons with a refractive error. (
  • There is convincing evidence that screening with a visual acuity test identifies persons with refractive error. (
  • Ranibizumab and bevacizumab had similar effects on visual acuity over a two-year period," the authors write. (
  • Follow-ups after 5-7 months showed not only complete maintenance of PL effects on visual acuity and contrast sensitivity function but also further improvement in these tasks. (
  • We hypothesize that the performance of specific adaptation and substitution exercises will result in an improvement in visual acuity during head movements while those patients performing placebo exercises will show no improvement. (
  • The primary endpoints of the trial were an improvement in visual acuity and a decrease in central subfield thickness at month 12. (
  • Objective:We measured the extent and duration of generalization effects to various spatial tasks (i.e., visual acuity, Vernier acuity, and foveal crowding) through PL on the target's contrast detection. (
  • The pre- and post-learning tasks included lateral interactions at different target-to-flankers separations (i.e., 2, 3, 4, 8λ) and included a range of spatial frequencies and stimulus durations as well as visual acuity, Vernier acuity, contrast-sensitivity function, and foveal crowding. (
  • We also found generalization of PL to different stimuli and tasks: contrast sensitivity for both trained and untrained spatial frequencies, visual acuity for Sloan letters, and foveal crowding, and partially for Vernier acuity. (
  • Vernier acuity is a type of visual acuity - more precisely of hyperacuity - that measures the ability to discern a disalignment among two line segments or gratings. (
  • A subject's vernier (IPA: /ˈvɜːrniər/ or /ˈvɜːniə/) acuity is the smallest visible offset between the stimuli that can be detected. (
  • Because vernier acuity exceeds acuity by far, the phenomenon has been termed hyperacuity. (
  • Vernier acuity develops rapidly during infancy and continues to slowly develop throughout childhood. (
  • However, vernier acuity decreases more quickly than grating acuity in peripheral vision. (
  • Vernier acuity was first explained by Ewald Hering in 1899, based on earlier data by Alfred Volkmann in 1863 and results by Ernst Anton Wülfing in 1892. (
  • Vernier acuity is resistant to defocus, motion, and luminance, but is subject to practice effects and changes in attention. (
  • Vernier acuity is measured by asking participants to judge the offset between two parallel line segments with both eyes (binocular vision) or with each eye individually (monocular vision). (
  • Vernier scale Stereoscopic acuity Snellen chart Westheimer, Gerald (1975). (
  • The researchers evaluated macular thickness measured by central subfield thickness (CST) and visual acuity at baseline, at the first post-lapse appointment, and at 3, 6 and 12 months after the lapse. (
  • ConclusionTopical DexNP significantly improve visual acuity and decrease macular thickness in patients with DME. (
  • The aim of this study was to evaluate the effects of hemodialysis (HD) on visual acuity, intraocular pressure (IOP), and central foveal thickness (CFT) in patients with chronic kidney disease. (
  • Bilateral vestibulopathy and age: experimental considerations for testing dynamic visual acuity on a treadmill. (
  • This can be assessed by testing Dynamic Visual Acuity (DVA) on a treadmill at different walking speeds. (
  • The dynamic visual acuity loss was calculated as the difference between visual acuity in the static condition and visual acuity in each walking condition. (
  • The dependency of the drop-out rate and dynamic visual acuity loss on BVP and age was investigated at all walking speeds, as well as the dependency of dynamic visual acuity loss on speed.Age and BVP significantly increased the drop-out rate (p ≤ 0.038). (
  • I-D Laplacian analysis of three occipital electrodes was significantly faster than conventional recording and analysis (Oz-Fz) at detecting ssVEP responses near visual acuity threshold (3' checks) from three years upwards, and at detecting responses to 6' and 9' checks in the 7-9 year age group. (
  • The results of the measurements further confirmed that having good visual acuity is necessary but not sufficient for good colour vision performance. (
  • The current study investigates a new method to objectively assess visual acuity in infants, which is uses a video gaze tracker (GT) and computer-generated stimuli, developed in the lab of M. Eizenman at the University of Toronto. (
  • ADCIS has developed an innovative mobile app to assess visual acuity in accordance with an American protocol. (
  • Bilateral vestibulopathy (BVP) can affect visual acuity in dynamic conditions, like walking. (
  • This prospective study found that the use of adalimumab appears to improve visual acuity and ocular inflammation in patients with refractory noninfectious childhood chronic uveitis. (
  • Target recognition tasks, which are most commonly used in clinical visual acuity measurements, require the recognition or naming of a target, such as with Snellen letters. (
  • ANSI Z80.21-2020 , Ophthalmics - Instruments - General-Purpose Clinical Visual Acuity Charts , applies to displays of optotypes for all clinical visual acuity measurement systems that use recognition of optotypes and that are designed for general use. (
  • Suppose a certain person's visual acuity is such that he can see objects clearly that term an image 4.00 μm high on his retina. (
  • To specify a person's visual acuity in terms of Snellen notation, a determination is made of the smallest line of letters of the chart that he/she can correctly identify. (
  • The visual acuity test is used to determine the smallest letters you can read on a standardized chart (Snellen chart) or a card held 20 feet (6 meters) away. (
  • The visual acuity test is a routine part of an eye examination or general physical examination, particularly if there is a change in vision or a problem with vision. (
  • Free Visual Acuity test that will help you detect problems with your vision, and identify the most common eye issues. (
  • Measurement app that records the results of the standard visual acuity test and intraocular pressure test. (
  • Brightness acuity test and outdoor visual acuity in cataract patients. (
  • The B.A.T. is a simple, repeatable, useful test for predicting functional outdoor acuity. (
  • Visual acuity is the quantifiable measure of the ability to identify black symbols on a white background at a standardized test distance. (
  • Seeking to benefit the eyesight of underprivileged children, around 600 of them were screened as part of a campaign organised here to test their visual acuity, officials said Wednesday. (
  • Chart with different orientation of the capital letter 'E' as used to test acuity of distance vision. (
  • There was no significant difference between the right and left eye acuities in binocular controls measured by the two techniques (paired t test). (
  • Sweep VEP techniques have a place for objectively studying acuity in infants and in those whose communication difficulties preclude other forms of behavioural test. (
  • Eye charts can be configured in various ways, but generally, if during an eye test you can read the big E at the top but none of the letters lower than that, your visual acuity is considered to be 6/60. (
  • Newark, California-based EyeQue has launched the EyeQue Insight visual acuity screener, a device that lets consumers test their vision at home. (
  • It attaches to a user's smartphone and lets them test their visual acuity as if they were in a much larger room. (
  • [1] An eye chart is a test of visual acuity, of your ability to make out fine detail. (
  • Purpose The purpose of this thesis was 1) to develop a test of visual acuity (VA) to measure recognition (form) acuity at a younger age than is currently clinically possible (3 years). (
  • 3) To test the feasibility of using infant's recognition VA tests to measure VA in infants 16 - 42 months of age in terms of the testability and ability to measure VA. Methods Preliminary study 1 - Development of Face targets: Adults participated and visual acuity for various versions of face targets were tested under blur in comparison to ETDRS or Tumbling E optotypes. (
  • Evidence that screening with a visual acuity test accurately identifies persons with cataracts is inadequate. (
  • Whereas VA and VF tests examine different aspects of the visual function, the progress made in the field of VF testing over the last 20 years might lead us to revisit the methodology used to test VA. (
  • A typical automated 24-2 visual field test assesses the vision threshold in 52 locations, attaching a numerical value to each location. (
  • In visual field testing, during the course of a full-threshold 24-2 VF test, 8 VF locations are routinely checked twice, to measure repeatability. (
  • If a 24-2 SITA visual field test takes under 7 minutes, determining the final threshold value reliably some 52 locations, shouldn't a comparable VA test take under 1 minute? (
  • You can even test additional visual characteristics like contrast and color sensitivity all from the comfort of your home. (
  • The approaches used to test the effects of an EE were consistent in showing significantly better preservation of cones and measurable visual acuity in 1-year-old rd10 EE mice. (
  • There was no decrease in visual acuity in the 14 normal patients, but there was a one to ten line decrease in vision among the cataract patients. (
  • Visual acuity in unilateral cataract. (
  • BACKGROUND: Patching the fellow eye in infancy is a well recognised therapy to encourage visual development in the lensectomised eye in cases of unilateral congenital cataract. (
  • Sweep VEPs were used to estimate acuity in 12 children aged between 4 and 16 years who had had a congenital cataract removed in the first 13 weeks of life. (
  • Study of Difluprednate vs. Prednisolone Acetate on Visual Acuity, and Corneal Edema Following Cataract Surgery. (
  • A Randomized, Masked Multi-center Safety & Efficacy Study of the Effects of Preoperative & Postoperative Cataract Surgery Use of Difluprednate Ophthalmic Emulsion, 0.05% Compared to Prednisolone Acetate Ophthalmic Suspension 1% on Visual Acuity & Corneal Edema. (
  • Eligibility for public-funded cataract surgery in New Zealand is assessed based on a weighted combination of visual acuity, cataract morphology and patient-reported quality of life. (
  • Clinical variables included best spectacle corrected visual acuity (BSCVA) in the eye prioritised for surgery alone and with both eyes open, cataract morphology, clinician-estimated visual potential, patient-reported impact on life and DHB of domicile. (
  • ocular motility dysfunction/eye movement disorders, vergence dysfunction/inefficiency in using both eyes together, strabismus/misalignment of the eyes, amblyopia/lazy eye, accommodative disorders/focusing problems, visual sensory disorders, and motor integration. (
  • Surprisingly, the end result of both these extreme regimens of reverse occlusion was the same, namely, a severe bilateral amblyopia in which the acuity of both eyes was permanently reduced to levels that were as low as 1/10, but more typically between 1/3 and 1/4 of normal values. (
  • Visual acuity screening of preterm infants. (
  • Visual acuity was screened in 36 healthy infants born 4 or more weeks prior to term. (
  • The results suggest that visual acuity is more closely correlated with age from conception than with age from birth and that visual acuity screening in preterm infants should be carried out with acuity gratings appropriate for the infant's postterm age rather than with acuity gratings appropriate for the infant's postnatal age. (
  • Overall, the results of this retrospective study suggest that pattern VER P1 latency may have important predictive power for later visual function in infants with an initially abnormal ophthalmologic examination. (
  • Purpose Early detection of abnormal visual acuity (VA) is crucial in the identification and management of ocular and visual abnormalities in infants. (
  • The mean TAC acuity over two visits for all the infants was 0.7±0.23 log cycles per degree, while the mean log GT acuity over two visits was 0.86±0.30. (
  • The majority of research investigating functional outcomes in human infants has repeatedly demonstrated better visual function related to the provision of DHA during the prenatal and postnatal periods in comparison to infants who were not supplemented. (
  • I wanted to quantify the link between regular visits to the eye doctor and visual outcomes for these patients. (
  • For all four metrics, patients who best adhered to their scheduled visits had better visual outcomes. (
  • However, when the Penn Medicine researchers controlled for number of injections, they found that visit adherence was still associated with visual outcomes, independent of how many treatments someone received. (
  • Further studies with larger case series are important to fully evaluate the overall reproducibility, patient satisfaction and visual outcomes. (
  • P = 0.03) compared with continued bevacizumab monotherapy while achieving similar visual outcomes (+5.4 letters vs. +4.9 letters) at one year. (
  • The purpose of this study was to evaluate the influence of target distance, target size, and visual acuity on vHIT outcomes. (
  • Preliminarily, visual acuity does not affect vHIT outcomes. (
  • This paper intoduces new principles for the design and use of letter charts for the measurement of visual acuity. (
  • Visual acuity should be reported on the basis of how the measurement was determined. (
  • The Landolt C and the Illiterate E are other forms of detection used in visual acuity measurement in the clinic. (
  • The change in visual acuity was calculated from subtracting the discharge measurement from the baseline measurement (pre-intervention). (
  • Conclusion The preference for faces, even with habituation, was not sufficiently strong in babies aged 3 - 15 months to use for recognition visual acuity measurement. (
  • Decrements in visual acuity during head movement in patients with vestibular hypofunction are potentially serious problems. (
  • The purpose of this study was to examine the effect of an exercise intervention on visual acuity during head movement in patients with unilateral and bilateral vestibular hypofunction. (
  • This side effect report can indicate a possible existence of increased vulnerability to Genteal Mild Lubricant Eye Drops (nvo) treatment in female patients suffering from NA, resulting in Visual Acuity Reduced . (
  • RESULTS: Patients with MA30/60 acrylic IOLs were significantly older, had a worse preoperative best corrected visual acuity (BCVA), and had more concomitant ocular diseases than those with SI-30/40 silicone IOLs. (
  • Oral and maxillofacial surgery teams receiving referrals of patients with these injuries have a vital role in ensuring that visual acuity (VA) is recorded at the time of presentation. (
  • For these patients at risk of permanent visual loss, prioritisation is assured and visual acuity and quality of life data is optional. (
  • Type 2 diabetic patients may be at an increased risk of declining visual acuity if they partake in moderate to heavy alcohol consumption. (
  • The success, duration and outcome of step_ VEP acuity assessment was compared to transient VEP (t-VEP) acuity assessment and subjective acuity assessment in a group of paediatric patients (N=218). (
  • Eliot L. Berson, M.D ., of the Massachusetts Eye and Ear, and Harvard Medical School, and colleagues analyzed visual acuity data from three clinical trials conducted involving patients with typical retinitis pigmentosa from 1984 to 1991, 1996 to 2001 and 2003 to 2008. (
  • Their results indicate that patients with a diet high in long-chain ω-3 fatty acids (≥0.20 g/d) had a 40 percent slower mean (average) annual rate of decline in distance visual acuity than those with a diet low in those fatty acids, the researchers comment. (
  • Patients receiving vitamin A palmitate, 15,000 IU/d, with ω-3 intake of at least 0.20 g/d had almost a 50 percent slower rate of decline in central visual field sensitivity than those receiving this dose of vitamin A with a lower ω-3 intake. (
  • Therefore, the treatment regimen of vitamin A combined with an ω-3-rich diet (≥0.20 g/d) should make it possible for many patients with typical retinitis pigmentosa to retain both visual acuity and central visual field for most of their lives," the researchers conclude. (
  • The distance between the person's eyes and the testing chart is set so as to approximate "optical infinity" in the way the lens attempts to focus (far acuity), or at a defined reading distance (near acuity). (
  • In the expression 6/x vision, the numerator (6) is the distance in metres between the subject and the chart and the denominator (x) the distance at which a person with 6/6 acuity would discern the same optotype. (
  • Visual acuity was assessed with the aid of a Snellen chart. (
  • Everyone who has been to the eye doctor or even the DMV has been tested with a visual acuity chart. (
  • The tumbling E chart tests the visual acuity of young children and others who can't read letters aloud. (
  • Studies have shown that visual acuity measurements using a tumbling E chart are virtually the same as those obtained from testing with a standard Snellen eye chart. (
  • Visual acuity should be measured from a standard distance, using a standard chart with a white background. (
  • Visual acuity and contrast sensitivity. (
  • Visual acuity can also be influenced by brightness, color, and contrast. (
  • Visual modeling suggests this may reflect a trade-off between colour discrimination and contrast detection. (
  • Pinakin Davey, DO, PhD, discusses the findings of his study comparing reliability of testing methodologies for visual acuity and contrast sensitivity at ARVO 2019. (
  • Visual acuity and contrast sensitivity are among the most common measures of visual abilities and a battery of tests exists to measure them. (
  • MD Mag: What did you find when comparing testing methodology for measuring visual acuity and contrast sensitivity? (
  • So, we chose a battery of tests, a group of tests, certain contrast sensitivity testing and certain visual acuity testing. (
  • EyeQue Insight only measures visual acuity, color vision, and contrast sensitivity. (
  • As as example, at twilight (morning or evening) as the natural light levels increase or decrease visual acuity changes. (
  • This experiment demonstrated the degradation in search performance resulting from a decrease in the frame rate of a static, structured display containing visual noise. (
  • The most commonly measured type, recognition visual acuity, is defined as the ability to discern certain optotypes (letters, numbers, or figures) at a specified distance. (
  • A simple and efficient way to state acuity is by converting the fraction to a decimal: 6/6 then corresponds to an acuity (or a Visus) of 1.0 (see Expression below), while 6/3 corresponds to 2.0, which is often attained by well-corrected healthy young subjects with binocular vision. (
  • Mean best corrected visual acuity (BCVA) at baseline in the control group was 59.2 letters compared with 58.9 letters in the study group. (
  • ISO 8596:2017 specifies a range of Landolt ring optotypes and describes a method for measuring distance visual acuity under photopic conditions for the purposes of certification or licensing. (
  • Accordingly, the rd10 EE mice at 1 year of age were still capable of performing the visual water task in photopic conditions, showing a residual visual acuity of 0.138±0 cycles/degree. (
  • Objective acuity assessment by Visual Evoked Potential (VEP) provides a complementary assessment in those subjects who cannot complete subjective tests. (
  • The aim of this study was to develop and evaluate a rapid, objective visual acuity assessment. (
  • Step_ VEPs were 16% more successful than t-VEPs and 9% more successful than subjective tests in providing a complete acuity assessment. (
  • Results of a 12-month study of eyes with persistent diabetic macular edema (DME) after multiple anti-vascular endothelial growth factor (anti-VEGF) injections indicate that a dexamethasone implant combined with bevacizumab improves visual acuity and macular morphology significantly. (
  • Neither peripheral acuity, foveal acuity, nor eye-dominance scores correlated significantly with search time. (
  • Results revealed that pattern-reversal VER P1 latency was predictive (87%) of whether visual acuity was equal to (or better than) or worse than 20/100 and whether a patient would have good fixation behavior (fix and follow, FF) or poor fixation (no FF) (86%) (P less than .001). (
  • These images are a random sampling from a Bing search on the term "Visual Acuity. (
  • Neural factors that limit acuity are located in the retina or the brain (or the pathway leading there). (
  • The precise distance at which acuity is measured is not important as long as it is sufficiently far away and the size of the optotype on the retina is the same. (
  • MacuLogix Inc) can aid in the diagnosis of early-stage, or subclinical, age-related macular degeneration before visual loss occurs and even before structural changes are observed, and adds to the information obtained from retina cameras and OCT imaging. (
  • Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. (
  • A point spread function describes the light distribution on the retina of a point source in visual space. (
  • The study, published in Retina in 2015, also found that visual acuity changes were not superior to those obtained by continued bevacizumab monotherapy. (
  • It is very important that we be able to measure the visual function accurately as well as, is there a way to enhance the visual function in cases where you have these chronic degenerative diseases, which is taking away the function of the retina. (
  • Visual processing involves the retina, thalamus, and primary visual cortex and cognitive response to visual information involves the integration of various cortical regions. (
  • Outside of the United States, the visual acuity is expressed as a decimal number. (
  • Stating acuity as a decimal number is the standard in European countries, as required by the European norm (EN ISO 8596, previously DIN 58220). (
  • Some European countries specify their visual acuities in decimal form, which is simply the decimal of the Snellen fraction (Table 1). (
  • Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. (
  • The luminance of the background and of the target (visual acuity letter) was measured for five commonly used visual acuity screen materials. (
  • This article considers the limitations of the commonly used methods for measuring visual acuity, and explores the developments in the field to address these issues. (
  • There is adequate evidence that visual acuity testing does not accurately identify early age-related macular degeneration (AMD). (
  • Visual acuity tests may be performed in many different ways. (
  • The visual acuity tests were obtained using the Snellen letters while the Colour vision measurements were achieved through designed colour targets. (
  • The end result is the same in either case: a perceived improvement in acuity, which can be subjected to appropriate tests and measured. (
  • An ANS on visual acuity tests developed by the Z80 ANSI-accredited Standards Committee has recently been updated. (
  • An older offering, the Personal Vision Tracker, tests refraction numbers (spherical, cylindrical, and axis figures used to determine eyeglass prescriptions) but not visual acuity. (
  • After noticing these methodological differences between visual field and VA tests, we can ask why we so casually accept a testing procedure that does not stand up to other diagnostic procedures' standards. (
  • Visual acuity is typically measured while fixating, i.e. as a measure of central (or foveal) vision, for the reason that it is highest in the very center. (
  • At approximately three to twelve months old, it surpasses grating acuity in foveal vision in humans. (
  • Davey: The study is done in collaboration with UC Riverside and our fundamental question is: Can visual function be improved with either vitamin therapy or by exercises or actually combining the two can give you a more beneficial outcome? (
  • Moreover, at each of the 52 locations used in a visual field text, the outcome is on a continuous scale, divided into 40 discrete steps (from 1 dB to 40 dB). (
  • The equivalent metric measurements for visual acuity are 6/6 and 6/30, respectively. (
  • However, acuity in peripheral vision can be of equal importance in everyday life. (
  • Acuity declines towards the periphery first steeply and then more gradually, in an inverse-linear fashion (i.e. the decline follows approximately a hyperbola). (
  • The decline is according to E2/(E2+E), where E is eccentricity in degrees visual angle, and E2 is a constant of approximately 2 deg. (
  • In fact, each missed visit was associated with an average visual acuity letter score decline of 0.7. (
  • The results showed that moderate and heavy drinkers had 1.8 and 2.0 times the increased risk of a decline in visual acuity. (
  • Dizziness and visual complaints are common symptoms reported post-concussion. (
  • These charts facilitate the use of nonstandard testing distances which might be used when there is low visual acuity, when examination room layout prevents testing at the standard distance, or when it is necessary to validate visual acuity scores or detect malingering. (
  • Adjusting the visual acuity score according to the chosen testing distance is simplified by the use of logarithmic scaling. (
  • This is called distance visual acuity testing. (
  • The idea is that you find the distance at which it looks like a gray box, and that is the visual acuity viewing distance for your display. (
  • The point at which you stop seeing a black and white checkerboard and see instead a gray box is the visual acuity viewing distance for your LCD monitor and your eyeball. (
  • So, what is your visual acuity viewing distance? (
  • The calculation I used predicts a visual acuity distance of 36.4 inches for your display, so your results roughly correspond to the generalized rule. (
  • Visual acuity (VA) is a measure of the ability of the eye to distinguish shapes and the details of objects at a given distance. (
  • PPP is a surgical maneuver performed in cases of higher-order aberrations, and it has been documented to enhance the visual potential by inducing a pinhole effect (Figures 1 and 2). (
  • The pinhole effect blocks distorted and unfocused light rays emanating from the peripheral cornea and isolates more focused central and paracentral rays through the central aperture, thereby enhancing visual acuity and image quality. (