Vision Tests: A series of tests used to assess various functions of the eyes.Color Perception Tests: Type of vision test used to determine COLOR VISION DEFECTS.Color Vision Defects: 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.Glare: 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)Vision Disorders: 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).Visual Acuity: Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.Contrast Sensitivity: 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.Vision, Ocular: The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.Vision, Low: 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.).Vision, Binocular: The blending of separate images seen by each eye into one composite image.Night Vision: 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.Vision, Monocular: Images seen by one eye.Blindness: 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.Color Perception: Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.Visually Impaired Persons: Persons with loss of vision such that there is an impact on activities of daily living.Visual Fields: The total area or space visible in a person's peripheral vision with the eye looking straightforward.Eyeglasses: 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.Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Sensory Aids: Devices that help people with impaired sensory responses.Vision Disparity: The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye.Retinal Cone Photoreceptor Cells: 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.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Amblyopia: 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.Diagnostic Techniques and Procedures: Methods, procedures, and tests performed to diagnose disease, disordered function, or disability.Abbreviations as Topic: Shortened forms of written words or phrases used for brevity.Color Vision: 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).Aviation: Design, development, manufacture, and operation of heavier-than-air AIRCRAFT.Certification: Compliance with a set of standards defined by non-governmental organizations. Certification is applied for by individuals on a voluntary basis and represents a professional status when achieved, e.g., certification for a medical specialty.BostonOrthoptics: The study and treatment of defects in binocular vision resulting from defects in the optic musculature or of faulty visual habits. It involves a technique of eye exercises designed to correct the visual axes of eyes not properly coordinated for binocular vision.Hospitals, Pediatric: Special hospitals which provide care for ill children.Asthenopia: Term generally used to describe complaints related to refractive error, ocular muscle imbalance, including pain or aching around the eyes, burning and itchiness of the eyelids, ocular fatigue, and headaches.Ocular Motility Disorders: Disorders that feature impairment of eye movements as a primary manifestation of disease. These conditions may be divided into infranuclear, nuclear, and supranuclear disorders. Diseases of the eye muscles or oculomotor cranial nerves (III, IV, and VI) are considered infranuclear. Nuclear disorders are caused by disease of the oculomotor, trochlear, or abducens nuclei in the BRAIN STEM. Supranuclear disorders are produced by dysfunction of higher order sensory and motor systems that control eye movements, including neural networks in the CEREBRAL CORTEX; BASAL GANGLIA; CEREBELLUM; and BRAIN STEM. Ocular torticollis refers to a head tilt that is caused by an ocular misalignment. Opsoclonus refers to rapid, conjugate oscillations of the eyes in multiple directions, which may occur as a parainfectious or paraneoplastic condition (e.g., OPSOCLONUS-MYOCLONUS SYNDROME). (Adams et al., Principles of Neurology, 6th ed, p240)Convergence, Ocular: The turning inward of the lines of sight toward each other.Soybeans: An annual legume. The SEEDS of this plant are edible and used to produce a variety of SOY FOODS.Petroleum: Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.Motor Vehicles: AUTOMOBILES, trucks, buses, or similar engine-driven conveyances. (From Random House Unabridged Dictionary, 2d ed)Prune Belly Syndrome: A syndrome characterized by abdominal wall musculature deficiency, cryptorchism, and urinary tract abnormalities. The syndrome derives its name from its characteristic distended abdomen with wrinkled skin.Automobile Driving: The effect of environmental or physiological factors on the driver and driving ability. Included are driving fatigue, and the effect of drugs, disease, and physical disabilities on driving.Accidents, Traffic: Accidents on streets, roads, and highways involving drivers, passengers, pedestrians, or vehicles. Traffic accidents refer to AUTOMOBILES (passenger cars, buses, and trucks), BICYCLING, and MOTORCYCLES but not OFF-ROAD MOTOR VEHICLES; RAILROADS nor snowmobiles.Investments: Use for articles on the investing of funds for income or profit.Brain Concussion: A nonspecific term used to describe transient alterations or loss of consciousness following closed head injuries. The duration of UNCONSCIOUSNESS generally lasts a few seconds, but may persist for several hours. Concussions may be classified as mild, intermediate, and severe. Prolonged periods of unconsciousness (often defined as greater than 6 hours in duration) may be referred to as post-traumatic coma (COMA, POST-HEAD INJURY). (From Rowland, Merritt's Textbook of Neurology, 9th ed, p418)Congresses as Topic: Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.Societies, Medical: Societies whose membership is limited to physicians.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Bibliography of Medicine: A list of works, documents, and other publications on medical subjects and topics of interest to the field of medicine.Vatican CityColoradoRadio Waves: Electromagnetic waves with frequencies between about 3 kilohertz (very low frequency - VLF) and 300,000 megahertz (extremely high frequency - EHF). They are used in television and radio broadcasting, land and satellite communications systems, radionavigation, radiolocation, and DIATHERMY. The highest frequency radio waves are MICROWAVES.Contraception: Prevention of CONCEPTION by blocking fertility temporarily, or permanently (STERILIZATION, REPRODUCTIVE). Common means of reversible contraception include NATURAL FAMILY PLANNING METHODS; CONTRACEPTIVE AGENTS; or CONTRACEPTIVE DEVICES.History, 20th Century: Time period from 1901 through 2000 of the common era.History, 19th Century: Time period from 1801 through 1900 of the common era.Catholicism: The Christian faith, practice, or system of the Catholic Church, specifically the Roman Catholic, the Christian church that is characterized by a hierarchic structure of bishops and priests in which doctrinal and disciplinary authority are dependent upon apostolic succession, with the pope as head of the episcopal college. (From Webster, 3d ed; American Heritage Dictionary, 2d college ed)