Browse plain-English disease and condition guides, including symptoms, causes, diagnosis, treatment options, prevention, and when to seek medical care.
Persistent Hyperplastic Primary Vitreous (PHPV)—now more often called Persistent Fetal Vasculature (PFV) is a congenital (present at birth) eye condition. In a developing baby, the eye has...
Read articleAblepharon-Macrostomia Syndrome (AMS) is an extremely rare, autosomal dominant genetic disorder characterized principally by absent or underdeveloped eyelids (“ablepharon”) and an unusually wide, fish-like mouth (“macrostomia”)...
Read articleAcanthamoeba keratitis is a rare but potentially sight-threatening corneal infection caused by the free-living amoeba Acanthamoeba, which is found ubiquitously in soil, fresh water, and even...
Read articleAccommodative esotropia is a common form of childhood strabismus in which one or both eyes turn inward (esodeviation) because of excessive focusing (accommodation) linked to farsightedness...
Read articleAchromatopsia is a rare eye condition that affects how a person sees color. People with achromatopsia typically have trouble seeing colors or can only see them...
Read articleAchromatopsia is a rare, inherited vision disorder that causes a complete or partial inability to see color. People with achromatopsia rely almost entirely on their rod...
Read articleAchromatopsia 2 (ACHM2) is a genetic eye condition that starts from birth. It mainly affects the cone cells in the retina, which are the light-sensing cells...
Read articleAcquired Developmental Prosopagnosia, often referred to as ADP, is a condition that affects a person’s ability to recognize faces. It’s a complex condition, and in this...
Read articleAcquired ectropion uveae (AEU) is a condition in which the pigmented posterior layer of the iris—normally hidden on the back surface—becomes adherent to and everts onto...
Read articleAcquired oculomotor nerve palsy is a non-congenital condition in which the third cranial nerve (oculomotor nerve) becomes damaged after birth, leading to dysfunction of most extraocular...
Read articleAcquired ophthalmoparesis is a condition characterized by weakness or paralysis of one or more extraocular muscles—those that control eye movements—due to processes that occur after birth....
Read articleAcquired Orbital Dysmorphia (AOD) is a medical condition that affects the structure and appearance of the eye socket and surrounding areas. In simpler terms, it means...
Read articleIncomplete color blindness means a person’s eyes and brain do not read color in the usual way. Colors may look faded, mixed up, or too similar....
Read article“Eye zone of injury” describes how far back into the eye wall an injury has gone. Doctors divide the globe (the eyeball itself) into zones to...
Read articleZinc optic neuropathy means damage to the optic nerve—the cable that carries visual signals from the eye to the brain—caused primarily by a lack of zinc...
Read articleEye Zika Virus means eye problems caused by infection with the Zika virus. Zika is a virus spread mainly by Aedes mosquitoes. It can also spread...
Read articleXerophthalmia is the medical name for eye disease caused by vitamin A deficiency. “Xero” means dry, and “ophthalmia” means a problem in the eyes. When the...
Read article“Xen glaucoma” is not a separate disease. It usually means glaucoma that is being treated (or planned to be treated) with a XEN Gel Stent, or...
Read articleXanthelasma (often called xanthelasma palpebrarum) is a harmless, yellow, soft patch that grows on the eyelids, most often near the inner corner and along the upper...
Read articleX-linked retinoschisis (XLRS) is a genetic eye condition that mostly affects boys and men. It causes the retina—the light-sensing “film” lining the back of the eye—to...
Read articleThe condition recognized in the medical literature is X-linked endothelial corneal dystrophy (XECD). Despite the word “anterior” in your prompt, XECD primarily involves the posterior cornea—especially...
Read articleA Wolfring gland ductal cyst is a fluid-filled sac that forms in the tiny tear-making tubes (ducts) of the accessory lacrimal glands of Wolfring. These accessory...
Read articleWolfram syndrome (often called WFS or DIDMOAD) is a rare, genetic, multi-system disorder that usually begins in childhood or the teen years. The nickname DIDMOAD comes...
Read articleWipe-out, also called snuff-out, is a sudden, severe, and usually irreversible loss of the remaining central vision that can happen soon after glaucoma surgery (most often...
Read articleKayser–Fleischer ring is a golden-brown to greenish ring seen at the edge of the cornea (the clear front window of the eye). It forms when excess...
Read articleWilson’s disease is a rare inherited condition where the body cannot handle copper properly. A gene change (ATP7B) disables a protein that should move extra copper...
Read articleWhite-Eyed Blow-Out Fracture is a special kind of orbital blow-out fracture that usually happens in children and teenagers. The orbit is the bony socket that holds...
Read articleA white cataract is a very dense, advanced cataract in which the normally clear lens of the eye has turned opaque and looks white when you...
Read articleWest Nile retinopathy means inflammation and injury to the light-sensing layers at the back of the eye (the retina and choroid) caused by the West Nile...
Read articleWest African Crystalline Maculopathy is an eye condition where tiny, shiny, yellow-green crystals collect in the very center of the retina (the fovea, the part that...
Read articleWest African Crystalline Retinopathy is a rare eye condition seen mostly in people of West African origin. Doctors see tiny, shiny, yellow-green “crystals” clustered at the...
Read articleA Wessely Immune Ring is a thin, gray-white ring that appears inside the clear part of the eye (the cornea). The ring sits within the corneal...
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