Common Vocabulary in Eye Reports

By: Carmen Willings
teachingvisuallyimpaired.com
Updated June 13, 2025

A–C

  • Accommodation. The eye's ability to adjust its focus for seeing at different distances. This is accomplished by changes in the shape of the lens through contraction of the ciliary muscles.
  • Adventitiously Blind. Describes someone who became blind after birth, typically due to accident or disease.
  • Amblyopia ("Lazy Eye"). A vision development disorder in which one eye fails to achieve normal visual acuity, even with prescription lenses. Often due to strabismus or lack of use.
  • Anterior Segment. Front portion of the eye, including the cornea, iris, and lens.
  • Astigmatism. A refractive error caused by an irregularly shaped cornea or lens that distorts vision at all distances.
  • Bilateral. Affects both eyes.
  • Binocular Vision. The ability to use both eyes together to produce a single, three-dimensional image.
  • Blindness. A severe reduction or absence of vision. Many individuals considered "blind" may still have some usable vision.
  • Central Vision. Vision in the direct line of sight; used for reading and recognizing faces.
  • Color Blindness. A reduced ability to distinguish certain colors, most commonly red and green. Usually inherited.
  • Congenital. A condition that is present at birth.
  • Congenitally Blind. Describes someone who has been blind since birth.
  • Convergence. The inward movement of both eyes as an object approaches, allowing for single binocular vision.
  • Convex Lens. A lens that bends light rays inward. Also called a plus lens, used to correct hyperopia (farsightedness).
  • Cortical Visual Impairment (CVI). Visual impairment caused by damage to the visual pathways or visual processing areas in the brain, rather than the eyes themselves.

D–F

  • Diplopia. Double vision caused by the eyes not aligning properly.
  • Doll’s Eye Phenomenon. ​An involuntary response in infants during the first weeks of life where the eyes move in the opposite direction of head movement.
  • Enucleation. Surgical removal of the entire eyeball.
  • Esophoria. A tendency for one eye to turn inward when fusion is disrupted.
  • Esotropia. A form of strabismus in which one or both eyes turn inward.
  • Exophoria. A tendency for one eye to turn outward when fusion is disrupted.
  • Exotropia. A form of strabismus in which one or both eyes turn outward.
  • Eye Dominance. The tendency of one eye to be the leading or preferred eye for visual input.
  • Field of Vision. The total area a person can see when the eyes are in a fixed position—about 180° horizontally and 120° vertically.
  • Fixation. The ability to maintain gaze on a single location.
  • Floaters. Small particles that drift through the vitreous humor, appearing as spots or cobwebs in one’s field of vision. Common with aging or retinal issues.
  • Focal Point. The spot where light rays meet after passing through a lens.
  • Follow (in “fix and follow”). Tracking a moving object with the eyes; often observed during functional vision assessments or infancy.
  • Functional Blindness. Vision may be present, but the individual primarily uses non-visual (tactile/auditory) methods for learning.
  • Functional Vision. How well a person uses their vision in everyday activities, regardless of acuity score.
  • Fusion. ​The brain’s ability to merge the two slightly different images from each eye into one coherent image.

G–L

  • Glaucoma. A group of diseases that damage the optic nerve, often associated with increased intraocular pressure.
  • Hemianopsia / Hemianopia. Loss of half the visual field in one or both eyes, typically due to brain injury or stroke.
  • Hyperopia. Farsightedness; distant objects are seen more clearly than close ones.
  • Hypertropia. Upward deviation of one eye.
  • Hypotropia. Downward deviation of one eye.
  • In Focus. An object is said to be in focus when it appears clearly defined and sharp.
  • -itis. A suffix meaning inflammation (e.g., conjunctivitis).
  • Legally Blind. Defined as visual acuity worse than 20/200 in the better eye with correction, or a visual field of 20 degrees or less in the better eye.
  • Light Adaptation. The eye’s adjustment to bright light conditions after being in the dark.
  • Low Vision. ​Significant visual impairment not correctable by standard glasses, surgery, or medication. Described in terms of acuity and/or field of vision.

M–P

  • Microphthalmia. A developmental disorder resulting in abnormally small eyeballs.
  • Monocular Vision. Vision using one eye only, often due to injury or removal of the other eye.
  • Myopia. Nearsightedness; close objects are seen clearly, while distant ones are blurry.
  • Night Blindness. Impaired vision in low-light or nighttime conditions.
  • Nystagmus. Involuntary, rapid, and repetitive movement of the eyes. May be horizontal, vertical, or rotary.
  • Occlusion / Patching. A treatment involving covering the stronger eye to encourage use of a weaker "lazy" eye.
  • Optic Atrophy. Damage or degeneration of the optic nerve resulting in vision loss.
  • Optic Nerve Hypoplasia (ONH). Underdevelopment of the optic nerve, often resulting in reduced visual acuity or field loss.
  • Partially Sighted. Describes vision that is limited (typically 20/70 to 20/200) and cannot be corrected with standard glasses.
  • Peripheral Vision. Vision at the edges of the visual field, outside the direct line of sight.
  • Photocoagulation. Use of a laser to treat eye conditions by sealing blood vessels or retinal tears.
  • Photophobia. Discomfort or sensitivity to light; often associated with other eye disorders.
  • Photoreceptors. Cells in the retina (rods and cones) that respond to light and send signals to the brain.
  • Pigmentation. Refers to coloration or presence of pigment in the eye or elsewhere.
  • Presbyopia. Age-related difficulty focusing on near objects due to decreased elasticity of the eye's lens.
  • Prism Lenses. ​Lenses shaped to bend light and help correct eye alignment or redirect vision for binocular function.
  • Ptosis. Drooping of the upper eyelid, potentially interfering with vision.

R–Z

  • Refraction / Refractive Error. The bending of light rays to focus on the retina. Refractive errors include conditions like myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.
  • Retina. The light-sensitive layer of tissue at the back of the eye that sends visual signals to the brain.
  • Retinopathy of Prematurity (ROP). A potentially blinding condition affecting premature infants, involving abnormal blood vessel growth in the retina.
  • Scotoma. An area of partial or complete loss of vision surrounded by a field of normal vision (blind spot).
  • Snellen Chart. The eye chart used to measure visual acuity (e.g., 20/20, 20/200).
  • Spherical Lens. A lens shaped like a segment of a sphere, used to correct refractive errors. Types include:
    • Biconvex (both surfaces curve outward)
    • Plano-convex (one side flat, one convex)
    • Biconcave (both surfaces curve inward)
    • Plano-concave (one side flat, one concave)
  • Strabismus. A misalignment of the eyes due to muscle imbalance. Types include:
    • Esotropia (eye turns inward)
    • Exotropia (eye turns outward)
    • Hypertropia (eye turns upward)
    • Hypotropia (eye turns downward)
  • Suppression. The brain’s process of ignoring visual input from one eye, often to avoid double vision.
  • Unilateral. Affects only one eye.
  • Visual Acuity. The clarity or sharpness of vision, typically measured by the ability to distinguish detail at a specific distance (e.g., 20/20 vision).
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