Melanoma-Associated Retinopathy (MAR) is an autoimmune eye condition linked to melanoma (usually cutaneous skin melanoma, sometimes uveal/eye melanoma). ...

Meige syndrome is a rare neurological condition. The brain circuits that normally smooth out and coordinate movement send faulty signals to the muscles of the ...

Along the edge of your eyelids—right behind your eyelashes—are tiny oil-making glands called meibomian glands. Each eyelid has dozens of them. They squeeze out ...

Megalopapilla means the optic disc (the “plug-in” point where the optic nerve enters the eye) is bigger than usual from birth. It’s a congenital (present at ...

Megalocornea means the clear front window of the eye (the cornea) is much larger than usual from birth, but the eye pressure is normal. Doctors usually make ...

Meesmann corneal dystrophy is a rare, inherited eye condition. “Inherited” means it runs in families and is passed from parent to child through genes. It ...

Medulloepithelioma is a very rare eye tumor that starts from the non-pigmented ciliary epithelium—a thin inner lining in the front part of the eye that helps ...

Medial ectropion / punctal eversion means the inner part of your lower eyelid tilts outward. Because the tear drain is no longer hugging the eyeball, tears ...

Medial canthal tendon avulsion means the small, tough band of tissue at the inner corner of your eyelids (near the nose) has been torn off its normal anchor on ...

Visual stress is a group of symptoms that happen when the eyes and brain struggle to handle certain visual input. The trigger can be bright light, flicker, ...

Meares–Irlen Syndrome (MIS) is a cluster of symptoms some people feel when they look at high-contrast text or busy visual patterns—especially black text on ...

Think of your eye’s natural lens as a grape inside a thin, see-through bag. That bag is the lens capsule. During cataract surgery, the cloudy “grape” is ...

Mask-associated dry eye (MADE) is dry, irritated, or uncomfortable eyes that start or get worse when you wear a face mask for long periods. In simple terms, ...

Maroteaux-Lamy syndrome is a rare, inherited condition where the body cannot break down certain natural “sugars” that help build connective tissues. These ...

Marginal keratitis is sterile inflammation at the outer edge of the cornea (the clear front window of your eye). It shows up as small white “infiltrates” a ...

Marfan syndrome is a genetic condition that weakens connective tissue—the “scaffolding” that holds the body together. Connective tissue is found almost ...

Marcus-Gunn jaw-winking ptosis is a condition—usually present from birth—where one upper eyelid droops at rest (ptosis) but flicks upward when the jaw moves, ...

Penetrating keratoplasty (PKP) is full-thickness corneal transplant surgery. During parts of the operation the eye is “open-sky”—the cornea is removed and the ...

The choroid is a thin layer full of blood vessels that sits behind your retina, inside the wall of the eye. A choroidal effusion happens when extra fluid ...

Submacular hemorrhage means bleeding under the central part of the retina called the macula. The macula is the tiny spot that gives you sharp, detailed, ...