Ophthalmology Glossary Cheat Sheet

Akinet­opsia. A disorder where indivi­duals struggle to perceive moving items.

Age-re­lated macular degene­ration (AMD). A predom­inant reason for vision impairment in indivi­duals over 50, impacting the macula which helps in distin­gui­shing fine details.

Amblyopia, also known as “lazy eye.” A visual disorder where one eye functions well while the other doesn’t. It emerges when the eyes aren't aligned or synchr­onize wrongly, leading to double vision. To rectify, the brain disregards one eye, affecting its visual capabi­lities.

Antagonist eye muscle. The muscle pulling the eye counter to the direction of the agonist muscle. When the agonist contracts, the antagonist relaxes.

Astigm­atism. A visual distur­bance causing unclear vision because the eye doesn't uniformly focus light on the retina. It’s akin to a magnifying lens with incons­istent curvatures causing a blurred image.

Binocular vision. The field of sight when both eyes function collec­tively.

Bipolar cells. Retinal nerve cells that handle initial visual data proces­sing. They get signals from the rods or cones and relay them to retinal ganglion cells connecting the brain.

Blepha­ritis. A chronic inflam­mation affecting the eyelash follicles on the eyelid­'s rim.

Blinds­ight. A phenomenon where indivi­duals can perceive objects in their blind visual area without conscious awareness. Despite reporting not seeing anything, their guesses about the object are accurate, indicating a subcon­scious form of vision.

Cataract. A cloudiness in the eye’s lens that obscures vision, creating a misty sight.

Central vision. The sharpest visual area when gazing directly using both eyes, crucial for reading and detailed observ­ation.

Compen­sation. In the realm of vision rehab, it often means intens­ifying eye movements toward the blind field to offset the vision loss.

Cones. Specia­lized retinal nerve cells accoun­table for color vision.

Cornea. The transp­arent external layer of the eye that influences focus by bending light in conjun­ction with the lens.

Cortical magnif­ication factor. A brain-­based enhanc­ement mechanism allowing central vision to be sharper than peripheral sight.

Diabetic eye diseases. Eye disorders predom­inantly in diabetics, like diabetic retino­pathy, leading to retinal tissue damage.

Diabetic retino­pathy. A diabet­es-­induced ailment caused by retinal blood vessel damage that can cause progre­ssive blindness.

Dilation. Pupil expansion to let in more light. Dilation, often induced using eyedrops, assists ophtha­lmo­logists in examining eyes effect­ively.

Donders test. A visual examin­ation where a finger is moved in and out of sight.

Dry eye. A state where the eye lacks sufficient moisture due to inadequate tear production or rapid evapor­ation, possibly due to infrequent blinking.

Enriched visual enviro­nment. A boosted visual setting with numerous or intricate visual stimuli. Used in studies to understand the brain's reaction compared to standard or diminished vision.

Extras­triate areas. Brain zones, beyond the primary visual cortex, attuned to motion, color, and percep­tion.

Extras­triate pathway. A swift brain commun­ication route separate from the main visual route, serving as an alert system. It permits the brain to sidestep the slower conscious proces­sing.

Eye yoga. A set of exercises focusing on enhancing eye muscle strength and visual capabi­lity, where muscles are system­ati­cally worked upon, enhancing strength and elasti­city.

Feature detection. The procedure of recogn­izing and scruti­nizing visual elements.

Field of view. The visible realm when eye movements occur, not to be mistaken for the “visual field” which is seen without eye movement.

Fovea. A small indent­ation in the retina’s macula crucial for perceiving color and intricate details.

Ganglion cells, also called retinal ganglion cells. These collect processed signals from bipolar cells and send this data to the brain via long extensions ending in the brain’s midsec­tion.

Glaucoma. Diseases risking vision or leading to blindness by harming the optic nerves. It can arise from elevated eye pressure or even with standard pressure, known as “normal tension glaucoma”.

Graves’ disease. An autoimmune disorder affecting the eye muscles usually necess­itating medica­tions and surgical interv­ent­ions.

Hemianopia or hemian­opsia. A visual impairment stemming from brain injuries or strokes, causing patients to perceive only half of an object in one or both eyes. This condition can also arise following surgeries to excise brain tumors near or within the visual pathway.

Hemifield. Refers to either the left or right half of what one sees.

Hetero­nymous. A visual discre­pancy where each eye sees differ­ently. For instance, one eye might have a blind spot in the upper left while the other has it in the lower right.

Homony­mous. A consistent visual issue in both eyes, like having blind spots in the same locations in both eyes.

Hyperopia or farsig­hte­dness. A vision condition where distant objects appear clear, but close ones do not. Glasses often correct this.

Iris. The eye's colored segment, regulating light entry by contro­lling the pupil's size, akin to a camera­'s aperture.

Ischemia. A reduction in blood flow that could harm the retina or brain. It may result from obstru­ctions like blood clots or from vessel spasms, possibly due to stress.

Lateral geniculate nucleus (LGN). A structure in the brain's thalamus that processes incoming visual signals from the retina. It's pivotal for sensory interp­ret­ation and movement, processing visual inform­ation..

Lazy eye. Also termed Amblyopia.

Lens. The eye's innate optical component, focusing light rays on the retina.

Low vision. Reduced visual capabi­lity, making day-to-day tasks challe­nging even with corrective measures like glasses or surgery.

Lutein. A vision­-sh­ielding vitamin found in leafy greens like spinach and kale, sourced from plants.

Macula. The retina­'s centermost portion, pivotal for clear central sight.

Micros­acc­ades. Minor, rapid eye twitches crucial for high-r­eso­lution vision; too subtle to see unaided.

Monocular vision. The vision from one eye when looking straight.

Muscular asthen­opia. A technical term indicating tired eyes.

Myopia or nearsi­ght­edness. A visual issue where nearby objects are clear, but distant ones are not, often rectified with glasses.

Occipital lobe. The brain region at the back, dedicated to vision proces­sing.

Open-angle glaucoma. A prevalent type of glaucoma caused by a buildup of eye fluid due to obstructed drainage channels.

Ophtha­lmo­logist. A physician specia­lizing in compre­hensive eye care, including surgeries.

Ophtha­lmo­scope. A tool combining mirrors and lenses, enabling doctors to inspect the eye's interior.
Optical coherence tomography (OCT). A non-in­vasive technique using infrared light to visualize the retina­'s different cellular layers.

Optic chiasm. The inters­ection point near the brain's base where optic nerve fibers from both eyes cross.

Optic nerve. The conduit carrying vision signals from the retina to the brain.

Optician. A profes­sional skilled in adjusting and repairing eyegla­sses.

Optic neuritis. An inflam­matory condition of the optic nerve. It can be painful and can lead to temporary vision loss. Despite the fact that MS is often connected with optic neuritis, not everyone who has the condition will go on to acquire MS.

Optic tract. The pathway following the optic chiasm, transp­orting visual inform­ation to the brain's thalamus and occipital lobe for proces­sing.

Optome­trist. A healthcare profes­sional trained in eye examin­ations and prescr­ibing corrective lenses but not qualified for surgeries.

Perimeter. Equipment used for a perimetry test to evaluate visual fields.

Perimetric charts. Visual diagrams resulting from field testing.

Perimetry test.An assessment of one's visual range using interm­ittent lights, done using a perimeter.

Peripheral vision. The side vision beyond the direct line of sight.

Photons.Elemental particles of light that are the fundam­ental units of electr­oma­gnetic radiation.

Photor­ece­ptors. Specia­lized nerve cells in the retina that convert light into nerve signals.

Preferred retinal location. The functional retinal sections people with central vision loss use for fixation. Also termed “eccentric fixation.”

Presby­opia. An age-re­lated decline in near-v­ision focus.

Pretectum. A brain stem section contro­lling pupil size.

Primary visual cortex (V1). A region in the occipital lobe's rear where visual interp­ret­ation commences.

Prism. A geometric optical element that bends light. Occasi­onally used to shift the missing visual field portion into a person­'s unimpaired visual field.

Pupils. The black centers in the eyes, the portals through which light enters. Iris-c­ont­rolled size adjust­ments determine the light amount entering.

Quadra­nta­nopia. A visual disorder akin to hemian­opia, but affecting roughly a quarter of the visual field, which can be in the upper or lower quadrant of one or both eyes.

Receptive field. A visual field segment where stimuli can activate specific nerve cells.

Refractive errors. Visual distur­bances caused by light not accurately focusing on the retina. These often lead to blurry vision and are linked to changes in the cornea, lens, or eye shape occurring in e.g. myopia, hyperopia, or astigm­atism.

Relative defect. A visual field region with compro­mised but not entirely lost vision. Determined using a perimetry test.

Residual vision. The remaining vision after a loss, typically referring to diminished but neither absent nor normal sight.

Retina. The tissue lining the eye's interior, respon­sible for converting light images to neural signals.

Retinitis pigmen­tosa. A hereditary eye disorder that damages the retina­'s photor­eceptor cells, potent­ially progre­ssing to total blindness.

Rods. Retinal nerve cells primarily sensitive to varying light intens­ities.

Saccadic eye movement training. Techniques teaching vision loss patients to expand their field of view through rapid, scanning eye movements.

Sclera. The white, sturdy outer layer encasing most of the eyeball.

Scotoma. A vision loss patch in the visual field due to an ailment, distinct from the innate blind spot.

Secondary visual cortex. The brain cortex section further handling inform­ation from the primary visual cortex or through the extras­triate route. This region contains multiple processing centers, such as V2, V3, V4, and V5, respon­sible for discerning colors, movements, and other visual features.

Sightb­lin­dness. Hidden visual deficits in an ostensibly normal visual field section, possibly resulting from a genera­lized decele­ration in brain inform­ation proces­sing.

Stereopsi loss. The loss of 3D vision or depth percep­tion, potent­ially due to ocular movement issues or brain injury. As a result, vision might seem two-di­men­sional.

Strabi­smus. A misali­gnment of the eyes often resulting from muscular coordi­nation issues.

Substi­tution. The approach of leveraging one sensory perception (like hearing) to compensate for anothe­r's loss (like sight).

Superior collic­ulus. A segment of the brain's tectum assisting with eye focusing, movement, and spatial orient­ation.

Supert­hre­shold perimetry. A method utilizing high-i­nte­nsity (or bright) light to assess the visual field, specif­ically to highlight the remaining vision capabi­lities.

Suprat­hre­shold perimetry. An evaluation employing low-in­tensity (or dim) illumi­nation to identify vision deficits.

Tectum. Situated in the brain's midpoint, this region harmonizes eye movements and merges visual data with inputs from other senses.

Tonometry. A diagnostic tool that gauges eye pressure, instru­mental in identi­fying glaucoma and related eye conditions arising from pressure imbala­nces.

Transo­rbital altern­ating current stimul­ation (tACS). A technique for vision restor­ation involving minor electric currents transm­itted to the eye via forehe­ad-­placed electr­odes. These currents induce simult­aneous firing (or synchr­oni­zation) of the retina­'s cells, bolstering existing vision.

Tunnel vision. A narrowed visual scope likened to observing through a tube or tunnel, limiting one's view to just a central patch.

Uveitis. An assortment of eye disorders charac­terized by inflam­mation, leading to swelling and potential tissue damage.

Visual acuity. A quanti­fic­ation of the clarity of someon­e's sight, where greater clarity corres­ponds to a higher resolu­tion.

Visual field. The total span visible when one's gaze remains forward, avoiding any eye or head movement.

Visual field border. The demarc­ation indicating the extent of one's sight without the need for head or eye movement.

Visual field chart. A graphical repres­ent­ation, based on perimetry test outcomes, detailing areas of clear vision, diminished (or residual) vision, and total vision loss.

Visual field tests. Evalua­tions gauging both central and peripheral visual capaci­ties.

Vision restor­ation training. A therap­eutic approach for indivi­duals with compro­mised vision, employing tailored exercises to invigorate nerve cells and expand visual range. The regimen commonly spans multiple months.

Vision therapy. A treatment regimen, predom­inantly managed by optome­trists, consisting of exercises tailored for the eyes and brain. It addresses issues such as amblyopia, strabi­smus, double vision, conver­gence defici­encies, and select learning and reading challe­nges.

Visual phantoms. Phenomena where indivi­duals with vision loss encounter halluc­ina­tions during periods when the brain undergoes active restor­ation and self-r­epair.

Visual template. Neural blueprints of standard shapes, forms, and objects ingrained from experi­ences in early youth. The brain consis­tently contrasts these templates with visual inputs to recognize surrou­nding entities.

Visual word form area. A term describing a brain region activated by both Braille reading and standard sighted reading, unders­coring its role in literary proces­sing.

Zeaxan­thin. A vitamin essential for vision protec­tion, sourced from plants. Paired with lutein, it's present in the yellow pigments of vegetables like leafy greens, fruits, and orange bell peppers.