Keratoendotheliitis fugax hereditaria (often shortened to KEFH) is a rare, inherited eye condition. People get short, repeat attacks where the clear window of ...

Keratoconus (pronounced keh-rah-toe-KOH-nus) is an eye condition where the cornea—the clear, dome-shaped “front window” of your eye—gets thinner and bulges ...

Keratoacanthoma (KA) is a fast-growing bump on the skin that looks like a small dome with a central “plug” of hard, yellow-brown material called keratin ...

Kearns–Sayre syndrome (KSS) is a rare mitochondrial disease—meaning the tiny “power plants” in our cells (mitochondria) don’t make enough energy. Classic KSS ...

Kawasaki disease (often shortened to “KD”) is an illness in young children that causes swelling and irritation of blood vessels (a “vasculitis”). It usually ...

Kasabach-Merritt Phenomenon (KMP) is a dangerous blood-clotting problem that happens in babies and young children who have a special kind of blood-vessel ...

Kabuki syndrome is a rare genetic condition present from birth. It affects how a child’s face, body, brain, and several organs develop and work. The name comes ...

Juvenile xanthogranuloma (JXG) is a benign (non-cancerous) skin condition in babies and young children. It belongs to a family of diseases called ...

Juvenile open-angle glaucoma (JOAG) is a glaucoma that shows up after early childhood (usually in the pre-teen, teen, or young-adult years) and before age ~40. ...

Juvenile idiopathic arthritis–associated uveitis — often shortened to JIA‑U — is inflammation inside the eye that happens in some children who have juvenile ...

“Junctional scotoma of Traquair” is a specific visual field loss pattern that happens when a lesion (often a tumor, cyst, aneurysm, or inflammation) sits right ...

A scotoma means a blind spot or patch of missing vision. You already have a normal “blind spot” where the optic nerve leaves the eye, but a pathologic scotoma ...

Joubert syndrome (JS) is a rare genetic condition that affects how the brain develops before birth. The main problem is in the back part of the brain called ...

Ivacaftor is a medicine used for cystic fibrosis (CF). In some children and teens who take ivacaftor (by itself or combined with other CF drugs), doctors have ...

An iris varix is a stretched-out, widened vein inside the colored part of your eye (the iris). Think of it as a tiny “varicose vein” of the iris. It usually ...

The iris is the round, colored part of your eye (brown, blue, green, etc.). It works like a camera aperture. A small ring of muscle inside the iris makes the ...