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Visual acuity

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Visual acuity (VA) commonly refers to the clarity of vision. [1]

142 relations: Aboriginal Australians, Amacrine cell, Amblyopia, Angular resolution, Anisometropia, Astigmatism, Binocular vision, Bipolar neuron, Bird of prey, Brain, Brain damage, Brainstem, Camera lens, Cataract, Cerebral cortex, Color blindness, Common logarithm, Cone cell, Contact lens, Contrast (vision), Cornea, Corrective lens, Cortical blindness, Cortical magnification, Critical period, Darmstadt, Decimal, Depth perception, Derivative, Deutsches Institut für Normung, Diabetes mellitus, Diffraction, Diffraction grating, Diffraction-limited system, Dioptre, E chart, Edmund Landolt, Eduard Jäger von Jaxtthal, Emmetropia, Encyclopædia Britannica, European Committee for Standardization, Evoked potential, Eye, Eye chart, Eye examination, Far-sightedness, Ferdinand Monoyer, Flashlight, Foot (unit), Fovea centralis, ..., Foveola, Fraction (mathematics), Fulldome, Ganglion cell, Glasses, Golovin–Sivtsev table, Hawk, Heinrich Küchler, Herman Snellen, Human eye, Hyperacuity (scientific term), Hyperbolic function, Infant, Infinity focus, Interferometry, Inverse trigonometric functions, Landolt C, Lateral geniculate nucleus, Leber's congenital amaurosis, Lens (anatomy), Light, Lighting, LogMAR chart, Macula of retina, Macular degeneration, Midbrain, Millimetre, Minute and second of arc, Multiple sclerosis, National Eye Institute, Nature (journal), Near-sightedness, Neoplasm, Nystagmus, Occipital lobe, Optic chiasm, Optic nerve, Optic radiation, Optic tract, Optical resolution, Optokinetic response, Pediatric ophthalmology, Perception, Peripheral vision, Photoreceptor cell, Photorefractive keratectomy, Pinhole occluder, Preferential looking, Presbyopia, Psychophysics, Pupil, Radian, Receptive field, Refractive error, Retina, Retinal detachment, Retinal mosaic, Retinal pigment epithelium, Retinal summation, Rod cell, Rotational speed, Scotopic vision, Second, Serif, Slab serif, Small-angle approximation, Snellen chart, Spatial frequency, Stereopsis, Stereoscopic acuity, Stevens's power law, Strabismus, Stroke, Subjective constancy, Subtended angle, Tapetum lucidum, Thalamus, Traumatic brain injury, Trigonometric functions, Troxler's fading, United States customary units, Utrecht, Vernier acuity, Vernier scale, Vienna, Virtual reality, Visual angle, Visual cortex, Visual field, Visual impairment, Visual perception, Weber–Fechner law. Expand index (92 more) »

Aboriginal Australians

Aboriginal Australians are legally defined as people who are members "of the Aboriginal race of Australia" (indigenous to mainland Australia or to the island of Tasmania).

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Amacrine cell

Amacrine cells are interneurons in the retina.

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Amblyopia

Amblyopia, also called lazy eye, is a disorder of sight due to the eye and brain not working well together.

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Angular resolution

Angular resolution or spatial resolution describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution.

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Anisometropia

Anisometropia is the condition in which the two eyes have unequal refractive power.

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Astigmatism

Astigmatism is a type of refractive error in which the eye does not focus light evenly on the retina.

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Binocular vision

In biology, binocular vision is a type of vision in which an animal having two eyes is able to perceive a single three-dimensional image of its surroundings.

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Bipolar neuron

A bipolar neuron or bipolar cell, is a type of neuron which has two extensions.

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Bird of prey

A bird of prey, predatory bird, or raptor is any of several species of bird that hunts and feeds on rodents and other animals.

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Brain

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.

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Brain damage

Brain damage or brain injury (BI) is the destruction or degeneration of brain cells.

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Brainstem

The brainstem (or brain stem) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord.

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Camera lens

A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.

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Cataract

A cataract is a clouding of the lens in the eye which leads to a decrease in vision.

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Cerebral cortex

The cerebral cortex is the largest region of the cerebrum in the mammalian brain and plays a key role in memory, attention, perception, cognition, awareness, thought, language, and consciousness.

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Christmas

Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.

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Christmas and holiday season

The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.

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Christmas Eve

Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.

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Christmas traditions

Christmas traditions vary from country to country.

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Color blindness

Color blindness, also known as color vision deficiency, is the decreased ability to see color or differences in color.

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Common logarithm

In mathematics, the common logarithm is the logarithm with base 10.

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Cone cell

Cone cells, or cones, are one of three types of photoreceptor cells in the retina of mammalian eyes (e.g. the human eye).

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Contact lens

A contact lens, or simply contact, is a thin lens placed directly on the surface of the eye.

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Contrast (vision)

Contrast is the difference in luminance or colour that makes an object (or its representation in an image or display) distinguishable.

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Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber.

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Corrective lens

A corrective lens is a lens typically worn in front of the eye to improve vision.

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Cortical blindness

Cortical blindness is the total or partial loss of vision in a normal-appearing eye caused by damage to the brain's occipital cortex.

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Cortical magnification

Cortical magnification describes how many neurons in an area of the visual cortex are 'responsible' for processing a stimulus of a given size, as a function of visual field location.

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Critical period

In developmental psychology and developmental biology, a critical period is a maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli.

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Darmstadt

Darmstadt is a city in the state of Hesse in Germany, located in the southern part of the Rhine-Main-Area (Frankfurt Metropolitan Region).

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Decimal

The decimal numeral system (also called base-ten positional numeral system, and occasionally called denary) is the standard system for denoting integer and non-integer numbers.

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Depth perception

Depth perception is the visual ability to perceive the world in three dimensions (3D) and the distance of an object.

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Derivative

The derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value).

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Deutsches Institut für Normung

Deutsches Institut für Normung e.V. (DIN; in English, the German Institute for Standardization) is the German national organization for standardization and is the German ISO member body.

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Diabetes mellitus

Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic disorders in which there are high blood sugar levels over a prolonged period.

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Diffraction

--> Diffraction refers to various phenomena that occur when a wave encounters an obstacle or a slit.

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Diffraction grating

In optics, a diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams travelling in different directions.

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Diffraction-limited system

The resolution of an optical imaging system a microscope, telescope, or camera can be limited by factors such as imperfections in the lenses or misalignment.

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Dioptre

A dioptre (British spelling) or diopter (American spelling) is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres.

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E chart

An E chart, also known as a tumbling E chart, is an ophthalmological chart used to measure a patient's visual acuity.

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Edmund Landolt

Landolt, Edmund, (17 May 1846 – 9 May 1926) was a Swiss ophthalmologist stationed in Paris, mostly known for a wide range of publications and his research in the field of ophthalmology.

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Eduard Jäger von Jaxtthal

Eduard Jäger von Jaxtthal (June 25, 1818, Vienna – July 5, 1884, Vienna) was an Austrian ophthalmologist who was a native of Vienna.

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Emmetropia

Emmetropia is the state of vision where a faraway object at infinity is in sharp focus with the eye lens in a neutral or relaxed state.

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Encyclopædia Britannica

The Encyclopædia Britannica (Latin for "British Encyclopaedia"), published by Encyclopædia Britannica, Inc., is a general knowledge English-language encyclopaedia.

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European Committee for Standardization

The European Committee for Standardization (CEN, Comité Européen de Normalisation) is a public standards organization whose mission is to foster the economy of the European Union (EU) in global trading, the welfare of European citizens and the environment by providing an efficient infrastructure to interested parties for the development, maintenance and distribution of coherent sets of standards and specifications.

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Evoked potential

An evoked potential or evoked response is an electrical potential recorded from the nervous system of a human or other animal following presentation of a stimulus, as distinct from spontaneous potentials as detected by electroencephalography (EEG), electromyography (EMG), or other electrophysiologic recording method.

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Eye

Eyes are organs of the visual system.

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Eye chart

An eye chart is a chart used to measure visual acuity.

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Eye examination

An eye examination is a series of tests performed by an ophthalmologist (medical doctor), optometrist, or orthoptist assessing vision and ability to focus on and discern objects, as well as other tests and examinations pertaining to the eyes.

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Far-sightedness

Far-sightedness, also known as hyperopia, is a condition of the eye in which light is focused behind, instead of on, the retina.

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Ferdinand Monoyer

Ferdinand Monoyer (9 May 1836 – 11 July 1912) was a French ophthalmologist, known for introducing the dioptre in 1872.

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Flashlight

A flashlight (more often called a torch outside North America) is a portable hand-held electric light.

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Foot (unit)

The foot (feet; abbreviation: ft; symbol: ′, the prime symbol) is a unit of length in the imperial and US customary systems of measurement.

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Fovea centralis

The fovea centralis is a small, central pit composed of closely packed cones in the eye.

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Foveola

The foveola is located within a region called the macula, a yellowish, cone photo receptor filled portion of the human retina.

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Fraction (mathematics)

A fraction (from Latin fractus, "broken") represents a part of a whole or, more generally, any number of equal parts.

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Fulldome

Fulldome refers to immersive dome-based video projection environments.

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Ganglion cell

A ganglion cell is a cell found in a ganglion.

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Glasses

Glasses, also known as eyeglasses or spectacles, are devices consisting of glass or hard plastic lenses mounted in a frame that holds them in front of a person's eyes, typically using a bridge over the nose and arms which rest over the ears.

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Golovin–Sivtsev table

The Golovin–Sivtsev Table (Таблица Головина-Сивцева) is a standardized table for testing visual acuity, which was developed in 1923 by Soviet ophthalmologists Sergei Golovin and D. A. Sivtsev.

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Hawk

Hawks are a group of medium-sized diurnal birds of prey of the family Accipitridae.

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Heinrich Küchler

Heinrich Georg Küchler (23 April 1811, Darmstadt – 29 March 1873, Darmstadt) was a German ophthalmologist.

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Herman Snellen

Herman Snellen (February 19, 1834 – January 18, 1908) was a Dutch ophthalmologist who introduced the Snellen chart to study visual acuity (1862).

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Human eye

The human eye is an organ which reacts to light and pressure.

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Hyperacuity (scientific term)

The sharpness of our senses is defined by the finest detail we can discriminate.

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Hyperbolic function

In mathematics, hyperbolic functions are analogs of the ordinary trigonometric, or circular, functions.

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Infant

An infant (from the Latin word infans, meaning "unable to speak" or "speechless") is the more formal or specialised synonym for "baby", the very young offspring of a human.

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Infinity focus

In optics and photography, infinity focus is the state where a lens or other optical system forms an image of an object an infinite distance away.

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Interferometry

Interferometry is a family of techniques in which waves, usually electromagnetic waves, are superimposed causing the phenomenon of interference in order to extract information.

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Inverse trigonometric functions

In mathematics, the inverse trigonometric functions (occasionally also called arcus functions, antitrigonometric functions or cyclometric functions) are the inverse functions of the trigonometric functions (with suitably restricted domains).

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Landolt C

A Landolt C, also known as a Japanese Vision Test, Landolt ring or Landolt broken ring, is an optotype, i.e. a standardized symbol used for testing vision.

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Lateral geniculate nucleus

The lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a relay center in the thalamus for the visual pathway.

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Leber's congenital amaurosis

Leber's congenital amaurosis (LCA) is a rare inherited eye disease that appears at birth or in the first few months of life.

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Lens (anatomy)

The lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina.

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Light

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.

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Lighting

Lighting or illumination is the deliberate use of light to achieve a practical or aesthetic effect.

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LogMAR chart

A LogMAR chart comprises rows of letters and is used by ophthalmologists, optometrists and vision scientists to estimate visual acuity.

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Macula of retina

The macula or macula lutea is an oval-shaped pigmented area near the center of the retina of the human eye and some other animalian eyes.

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Macular degeneration

Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred or no vision in the center of the visual field.

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Midbrain

The midbrain or mesencephalon (from Greek mesos 'middle', and enkephalos 'brain') is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation.

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Millimetre

The millimetre (International spelling as used by the International Bureau of Weights and Measures; SI unit symbol mm) or millimeter (American spelling) is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length.

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Minute and second of arc

A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.

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Multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged.

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National Eye Institute

The National Eye Institute (NEI) was established in 1968 and is located in Bethesda, Maryland.

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Nature (journal)

Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.

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Near-sightedness

Near-sightedness, also known as short-sightedness and myopia, is a condition of the eye where light focuses in front of, instead of on, the retina.

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Neoplasm

Neoplasia is a type of abnormal and excessive growth of tissue.

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New Year

New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.

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New Year's Day

New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.

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New Year's Eve

In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.

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Nystagmus

Nystagmus is a condition of involuntary (or voluntary, in rare cases) eye movement, acquired in infancy or later in life, that may result in reduced or limited vision.

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Occipital lobe

The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals.

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Optic chiasm

The optic chiasm or optic chiasma (Greek χίασμα, "crossing", from the Greek χιάζω 'to mark with an X', after the Greek letter 'Χ', chi) is the part of the brain where the optic nerves partially cross.

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Optic nerve

The optic nerve, also known as cranial nerve II, is a paired nerve that transmits visual information from the retina to the brain.

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Optic radiation

The optic radiation (also known as the geniculocalcarine tract, the geniculostriate pathway, and posterior thalamic radiation) are axons from the neurons in the lateral geniculate nucleus to the primary visual cortex.

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Optic tract

The optic tract (from the Latin tractus opticus) is a part of the visual system in the brain.

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Optical resolution

Optical resolution describes the ability of an imaging system to resolve detail in the object that is being imaged.

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Optokinetic response

The optokinetic response is a combination of a slow-phase and fast-phase eye movements.

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Pediatric ophthalmology

Pediatric ophthalmology is a sub-speciality of ophthalmology concerned with eye diseases, visual development, and vision care in children.

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Perception

Perception (from the Latin perceptio) is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information, or the environment.

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Peripheral vision

Peripheral vision is a part of vision that occurs only on the side gaze.

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Photoreceptor cell

A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction.

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Photorefractive keratectomy

Photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (or laser epithelial keratomileusis) (LASEK) are laser eye surgery procedures intended to correct a person's vision, reducing dependency on glasses or contact lenses.

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Pinhole occluder

A pinhole occluder is an opaque disk with one or more small holes through it, used by ophthalmologists, orthoptists and optometrists to test visual acuity.

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Preferential looking

Preferential looking is an experimental method in developmental psychology used to gain insight into the young mind/brain.

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Presbyopia

Presbyopia is a condition associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects.

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Psychophysics

Psychophysics quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they produce.

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Pupil

The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina.

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Radian

The radian (SI symbol rad) is the SI unit for measuring angles, and is the standard unit of angular measure used in many areas of mathematics.

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Receptive field

The receptive field of an individual sensory neuron is the particular region of the sensory space (e.g., the body surface, or the visual field) in which a stimulus will modify the firing of that neuron.

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Refractive error

Refractive error, also known as refraction error, is a problem with focusing light accurately onto the retina due to the shape of the eye.

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Retina

The retina is the innermost, light-sensitive "coat", or layer, of shell tissue of the eye of most vertebrates and some molluscs.

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Retinal detachment

Retinal detachment is a disorder of the eye in which the retina separates from the layer underneath.

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Retinal mosaic

Retinal mosaic is the name given to the distribution of any particular type of neuron across any particular layer in the retina.

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Retinal pigment epithelium

The pigmented layer of retina or retinal pigment epithelium (RPE) is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells.

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Retinal summation

Retinal summation describes the relationship between different types of cells in the retina: cone photoreceptor cells, bipolar cells, and ganglion cells.

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Rod cell

Rod cells are photoreceptor cells in the retina of the eye that can function in less intense light than the other type of visual photoreceptor, cone cells.

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Rotational speed

Rotational speed (or speed of revolution) of an object rotating around an axis is the number of turns of the object divided by time, specified as revolutions per minute (rpm), cycles per second (cps), radians per second (rad/s), etc..

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Scotopic vision

Scotopic vision is the vision of the eye under low-light levels.

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Second

The second is the SI base unit of time, commonly understood and historically defined as 1/86,400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.

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Serif

In typography, a serif is a small line attached to the end of a stroke in a letter or symbol.

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Slab serif

In typography, a slab serif (also called mechanistic, square serif, antique or Egyptian) typeface is a type of serif typeface characterized by thick, block-like serifs.

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Small-angle approximation

The small-angle approximation is a useful simplification of the basic trigonometric functions which is approximately true in the limit where the angle approaches zero.

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Snellen chart

A Snellen chart is an eye chart that can be used to measure visual acuity.

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Spatial frequency

In mathematics, physics, and engineering, spatial frequency is a characteristic of any structure that is periodic across position in space.

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Stereopsis

Stereopsis (from the Greek στερεο- stereo- meaning "solid", and ὄψις opsis, "appearance, sight") is a term that is most often used to refer to the perception of depth and 3-dimensional structure obtained on the basis of visual information deriving from two eyes by individuals with normally developed binocular vision.

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Stereoscopic acuity

Stereoscopic acuity, also stereoacuity, is the smallest detectable depth difference that can be seen in binocular vision.

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Stevens's power law

Stevens's power law is a proposed relationship between the magnitude of a physical stimulus and its perceived intensity or strength.

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Strabismus

Strabismus, also known as crossed eyes, is a condition in which the eyes do not properly align with each other when looking at an object.

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Stroke

A stroke is a medical condition in which poor blood flow to the brain results in cell death.

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Subjective constancy

Subjective constancy or perceptual constancy is the perception of an object or quality as constant even though our sensation of the object changes.

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Subtended angle

In geometry, an angle subtended by an arc, line segment, or other curve is one whose two rays pass through the endpoints of the arc.

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Tapetum lucidum

The tapetum lucidum (Latin: "bright tapestry; coverlet", plural tapeta lucida) is a layer of tissue in the eye of many vertebrates.

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Thalamus

The thalamus (from Greek θάλαμος, "chamber") is the large mass of gray matter in the dorsal part of the diencephalon of the brain with several functions such as relaying of sensory signals, including motor signals, to the cerebral cortex, and the regulation of consciousness, sleep, and alertness.

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Traumatic brain injury

Traumatic brain injury (TBI), also known as intracranial injury, occurs when an external force injures the brain.

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Trigonometric functions

In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are functions of an angle.

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Troxler's fading

Troxler's fading, or Troxler fading, or the Troxler effect, is an optical illusion affecting visual perception.

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United States customary units

United States customary units are a system of measurements commonly used in the United States.

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Utrecht

Utrecht is a city and municipality in the Netherlands, capital and most populous city of the province of Utrecht.

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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.

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Vernier scale

A vernier scale is a visual aid that allows the user to measure more precisely than could be done unaided when reading a uniformly divided straight or circular measurement scale.

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Vienna

Vienna (Wien) is the federal capital and largest city of Austria and one of the nine states of Austria.

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Virtual reality

Virtual reality (VR) is an interactive computer-generated experience taking place within a simulated environment, that incorporates mainly auditory and visual, but also other types of sensory feedback like haptic.

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Visual angle

The visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc.

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Visual cortex

The visual cortex of the brain is a part of the cerebral cortex that processes visual information.

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Visual field

The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments".

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Visual impairment

Visual impairment, also known as vision impairment or vision loss, is a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses.

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Visual perception

Visual perception is the ability to interpret the surrounding environment using light in the visible spectrum reflected by the objects in the environment.

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Weber–Fechner law

The Weber–Fechner law refers to two related laws in the field of psychophysics, known as Weber's law and Fechner's law.

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2018

2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.

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2019

2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.

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Redirects here:

20/20, 20/20 Vision, 20/20 vision, 6/6, Dynamic Visual Acuity, Dynamic visual acuity, Normal vision, Poor visual acuity, Sharpness of vision, Twenty-twenty vision.

References

[1] https://en.wikipedia.org/wiki/Visual_acuity

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