Uveitis is inflammation of the uveal tract—the iris, ciliary body, and choroid—of the eye. When this inflammation becomes severe or causes complications such as high intraocular pressure, infection, ...
An Anterior Chamber Intraocular Lens (AC IOL) is a specialized artificial lens designed to replace the eye’s natural lens when it cannot be safely placed in the usual location behind the iris (the ...
Anterior Capsular Contraction Syndrome (ACCS) is a postoperative complication of cataract surgery characterized by the progressive constriction and fibrotic shrinkage of the anterior capsulotomy (the ...
Anoxic brain injury occurs when the brain is deprived of oxygen long enough to cause cellular damage or death. In ophthalmology, this injury can disrupt the visual pathways—structures from the eyes ...
Anophthalmia is a rare congenital condition characterized by the complete absence of one or both eyes (the globe) and all associated ocular tissues within the eye socket (orbit). In affected ...
Anomalous Retinal Correspondence (ARC) is a sensory adaptation in which the brain learns to fuse images from two misaligned eyes by remapping the extra-foveal point of the deviated eye to correspond ...
Ankyloblepharon is a medical condition characterized by the adhesion or fusion of the edges of the upper eyelid with those of the lower eyelid, either completely or at discrete points along the lid ...
Anisometropic amblyopia, often called “lazy eye” caused by unequal refractive error, is a vision development disorder in which the brain favors one eye over the other. In this condition, a ...
Aniseikonia is a binocular vision disorder in which the images perceived by each eye differ in size or shape. In simple terms, an object viewed by one eye appears larger or smaller than when viewed ...
Aniridic Fibrosis Syndrome is a rare, sight-threatening complication that arises in patients with congenital aniridia—an eye condition marked by partial or complete absence of the iris—typically ...
Aniridia is a rare eye condition characterized by the complete or near-complete absence of the iris, the colored muscular ring that regulates how much light enters the eye. This absence produces a ...
Angle Recession Glaucoma (ARG) is a form of secondary open-angle glaucoma that develops after blunt injury to the eye. In this condition, trauma causes a tear—or “recession”—between the circular and ...
Angiolymphoid hyperplasia with eosinophilia (ALHE), also called epithelioid hemangioma, is a rare, benign vascular proliferation characterized by the growth of small blood vessels lined by plump, ...
Angioid streaks are irregular fissures or crack-like breaks in Bruch’s membrane, a thin, elastic layer that lies between the retina and the choroid. These streaks radiate outward from the optic disc ...
Angelman syndrome is a rare neuro-genetic disorder caused by the loss of function of the maternal UBE3A gene on chromosome 15. In most healthy individuals, both parents contribute one copy of UBE3A, ...
Amiodarone‐associated optic neuropathy (AAON) is a rare, drug‐induced damage to the optic nerve that occurs in patients receiving amiodarone for cardiac arrhythmias. Clinically, AAON presents with an ...
Amblyopia, commonly known as “lazy eye,” is a vision development disorder in which an eye fails to achieve normal visual acuity—sharpness—even with prescription glasses or contact lenses. It results ...
Transient vision loss (TVL) refers to a temporary loss of vision, either partial or complete, in one or both eyes, lasting from a few seconds up to 24 hours. It can manifest as a sudden darkening, ...
Amaurosis fugax is a transient, painless loss of vision in one or both eyes, typically lasting from seconds to minutes before returning to normal. It occurs when blood flow to the retina or optic ...
Amantadine-induced corneal edema is a rare but recognized toxic reaction in which the drug amantadine damages the inner cell layer of the cornea (the endothelium), leading to fluid buildup and ...
