Multiple Evanescent White Dot Syndrome (MEWDS) is an eye condition that suddenly appears, usually in one eye, in otherwise healthy people—most often young, ...
Dr. Mary A. Ahluwalia, MD - Ophthalmologist
Ocular features are the visible signs and measurable findings related to your eyes. They are the things an eye-care professional can see, feel, measure, or ...
Multiple Endocrine Neoplasia (MEN) is a group of inherited (passed down in families) conditions that make certain hormone-producing glands grow abnormally. ...
Muir-Torre Syndrome (MTS) is a hereditary (autosomal-dominant) cancer syndrome where people develop oil-gland (sebaceous) skin tumors and have a higher chance ...
Mucus Fishing Syndrome is a cycle where the eye makes extra stringy mucus because the surface is irritated. That extra mucus feels annoying, so a person keeps ...
Mucormycosis is a serious fungal infection. It happens when tiny fungus spores (from a group called Mucorales) enter the body—usually through the nose, ...
A mucocele is a soft, cyst-like swelling filled with mucus (slippery fluid) that forms when a mucus-carrying duct gets blocked or torn. Think of a thin tube ...
Morning Glory Anomaly (often shortened to MGDA) is a birth-time (congenital) change in the optic nerve head—the spot where the optic nerve enters the back of ...
A Morgagnian cataract is a very late, “over-ripe” cataract. By this stage, the soft, outer layers of the lens (the cortex) have liquefied—they turn into a ...
Morbihan disease (also called Morbihan syndrome, solid persistent facial edema, solid facial lymphedema, or rosacea-associated facial lymphedema) is a rare ...
Mooren’s ulcer is a rare, very painful sore at the edge of the cornea (the clear front window of the eye). It starts near the limbus (the border where the ...
Monovision LASIK is a vision correction procedure that intentionally leaves one eye slightly nearsighted while correcting the other eye for distance ...
Monofixation syndrome is a binocular-vision pattern where a person uses both eyes together for wide, peripheral vision, but does not use both foveas (the ...
Monocular Occipital Temporal Crescent Syndrome also known Temporal crescent syndrome, which occurs from a lesion in the anterior occipital cortex, however, is ...
Monocular Elevation Deficit (MED)—also called “double elevator palsy”—is when one eye cannot look up as it should. The problem looks the same whether that eye ...
Monkeypox is a contagious disease caused by the mpox virus, a member of the orthopoxvirus family (the same family as smallpox, but mpox is usually much ...
Molluscum contagiosum is a harmless but contagious skin infection caused by a poxvirus called the molluscum contagiosum virus (MCV). It makes small, smooth, ...
MOOKP is a special surgery for people who are blind from severe corneal and ocular surface disease and have very dry, scarred eyes. Surgeons take a small piece ...
A Mittendorf dot is a tiny, round, speck on the back surface of the lens (the clear focusing structure inside your eye). It is a harmless leftover from a baby ...
Minimally invasive glaucoma surgery (MIGS) is a group of very small, targeted eye operations that lower eye pressure (intraocular pressure, IOP) with much less ...
Retinal detachment means the thin, light-sensing layer at the back of your eye (the retina) gets lifted or pulled away from the healthy layer underneath it ...
Miller Fisher syndrome (MFS) is a rare immune-related nerve disorder. It is a variant of Guillain-Barré syndrome (GBS). In MFS, the body’s defense system ...
Millard–Gubler syndrome is a pattern of symptoms that happens when a small area in the front part of the pons (a short, thick section of the brainstem that ...
Milkweed corneal toxicity is an eye injury caused when the milky sap (latex) from certain “milkweed” plants gets into the eye. The sap contains natural ...
Migratory Serpiginous Corneal Epitheliopathy is a newly described, non-infectious corneal surface disorder. “Migratory” means the patches change location over ...
Microsporidia are extremely tiny germs that live inside the cells of people and animals. They make tough spores (like tiny seeds) that help them survive in the ...
Microspherophakia means the natural lens inside the eye is smaller than usual and more round (spherical) than normal. In a typical eye, the lens is like a ...
Chorioretinopathy is an umbrella term for conditions that harm the choroid (the eye’s blood-vessel layer) and the retina (the light-sensing film). When this ...
Microcephaly means a baby’s or child’s head is smaller than expected for their age and sex. Doctors measure the head with a soft measuring tape and compare the ...
Methamphetamine-induced keratitis is inflammation and injury of the clear front window of the eye (the cornea) that happens in people who use methamphetamine ...
Metastasis to the extraocular muscles means cancer cells from somewhere else in the body travel through the bloodstream and settle inside one or more of the ...
Metabolic keratopathy means your cornea (the clear front window of the eye) is getting sick because abnormal substances build up inside it, or because the ...
Merkel cell carcinoma (MCC) is a rare but very aggressive skin cancer that starts in the top layer of the skin. Under the microscope it looks like a “small ...
Pseudomembranous conjunctivitis is a type of severe eye surface inflammation. The thin skin that lines the inside of your eyelids and covers the white of your ...
Membranous conjunctivitis is a severe form of “pink eye” in which a sheet of tough material (a membrane or pseudo-membrane) forms on top of the moist surface ...
Melkersson–Rosenthal Syndrome (MRS) is a rare condition that mainly affects the face and mouth. Doctors describe a classic “triad” of features:...
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, ...
Ocular GVHD is eye inflammation and surface damage that can happen after an allogeneic (donor) bone-marrow or stem-cell transplant. Donor immune cells see ...
A Boston Keratoprosthesis (Boston KPro) is an artificial cornea. “Artificial cornea” means a clear, man-made window that a surgeon places in the front of the ...
A corneal perforation means there is a full-thickness hole in the cornea, the clear “window” at the front of your eye. The cornea keeps the eye sealed, focuses ...
A descemetocele is a dangerous “last-layer bulge” in the cornea that happens when an ulcer eats through almost all the corneal tissue, leaving only the inner ...
Malignant optic glioma is a cancer of the optic pathway (the cable system that carries visual signals from the eyes to the brain). In simple terms, “malignant” ...
Malignant melanoma of the eyelid is a dangerous skin cancer that starts in pigment-making cells (melanocytes) located in the thin skin of the upper or lower ...
Malarial retinopathy means changes in the back of the eye (the retina) that happen during severe malaria, most often with Plasmodium falciparum. The retina is ...
Malar means the cheekbone area. Doctors also call this the midface, because it sits in the middle third of the face, between the lower eyelid and the upper ...
Madarosis means you are losing the hairs of your eyelashes, your eyebrows, or both. The loss can be mild (thinning), patchy, or complete. It can happen on one ...
Macular telangiectasia (MacTel) is an eye condition that affects the macula, the tiny central area of the retina that gives you sharp, straight-ahead vision ...
A macular hole is a tiny, round gap that opens in the very center of the retina (the fovea), where our sharpest, most detailed vision lives. In a ...
Macular corneal dystrophy is a rare, inherited eye disease that makes the clear front window of the eye (the cornea) slowly turn cloudy. Tiny “spots” and a ...
Rhegmatogenous retinal detachment (RRD) is when the light-sensing layer at the back of your eye (the retina) peels away from the wall of the eye because a tear ...
Macula-on rhegmatogenous retinal detachment means the retina has peeled off because of a hole or tear, but the center of sight (the macula) is still attached. ...
A retinal arterial macroaneurysm is a balloon-like bulge that forms in a small artery on the surface of the retina (the light-sensing layer at the back of your ...
Cortical visual impairment (often called cerebral visual impairment) is a vision problem caused by how the brain processes visual information, not by a problem ...
Metamorphopsia means things look the wrong shape. Straight lines may look wavy or bent. A square window can look tilted, and printed letters may look crowded, ...
Nyctalopia means you cannot see well in low light. People with nyctalopia struggle at dusk, at night, or in dim rooms. It happens because the “night vision” ...
Patchy vision means parts of what you see are missing, faded, smudged, or oddly shaped—like someone cut small pieces out of your view or smeared a clear window ...
Diffuse blurred vision means your sight looks soft, hazy, or out of focus across most or all of what you see, not just in one small spot. It can affect one eye ...
Peripheral (side) vision loss means the edges of what you can see shrink or disappear. You may still see clearly straight ahead, but you miss what happens to ...
Central vision is the sharp, detailed sight you use to read, recognize faces, thread a needle, or see the small details in a picture. It lives in a tiny area ...
Lymphocytic choriomeningitis (often shortened to LCM) is an infection caused by the lymphocytic choriomeningitis virus (LCMV). This virus belongs to a family ...
Lyme disease is a bacterial infection you get from the bite of an infected black‑legged tick. The tick feeds on a small animal (often mice) that carries ...
Lower eyelid retraction means the lower eyelid sits too low on the eye. Instead of gently touching the lower edge of the colored part (the iris), the lid is ...
Lower eyelid blepharoplasty is a surgery that improves the look and shape of the lower eyelids. In plain words, it is a carefully planned procedure to treat ...
Lowe syndrome is a rare, inherited condition that mainly affects the eyes, the brain/nerves, and the kidneys—which is why doctors also call it ...
Low vision means your sight is permanently reduced in a way that regular glasses, contact lenses, medicine, or surgery cannot fully fix. People with low vision ...
Long Anterior Zonules (LAZ) means some of the tiny “guy-wire” fibers that hold your lens—the zonules—reach farther onto the front surface of the lens (called ...
African eye worm is the common name for Loa loa, a tiny thread-like parasite (a filarial worm) that lives and moves in the soft tissues under the skin and ...
Loa loa filariasis, also called loiasis (pronounced low-ah EYE-uh-sis), is a parasitic infection (an illness caused by a tiny living thing) due to Loa loa, a ...
Lisch corneal dystrophy is a genetic eye condition that affects the skin-like surface layer of the clear window of the eye (the corneal epithelium). Tiny ...
Lipid keratopathy means fat (lipid) gets deposited inside the clear front window of the eye, called the cornea. The cornea is normally crystal-clear and has no ...
Lipemia retinalis is a look that eye doctors see at the back of the eye when the fat in the blood (especially triglycerides carried in “chylomicrons”) is ...
Linear interstitial keratitis is a very rare form of corneal inflammation in which a line-shaped streak appears inside the stroma (the middle, transparent ...
Your cornea (the clear “window” at the front of the eye) is covered by a very thin skin called the corneal epithelium. That skin constantly wears out and must ...
Ligneous conjunctivitis is a rare kind of long-lasting, often-returning “pink eye” where thick, wood-like (“ligneous”) layers—called pseudomembranes—build up ...
Light–near dissociation means the pupil doesn’t shrink to light, but does shrink when you look at something near. It’s a sign, not a disease. Think of it as a ...
Linear interstitial keratitis (LIK) is a non-ulcerative, line-shaped inflammatory streak inside the cornea’s stromal layer. It looks like a straight, pale or ...
Your cornea is the clear “window” at the front of the eye. Its skin-like surface (called the corneal epithelium) is constantly renewed by special repair cells ...
Ligneous conjunctivitis is a rare, long-lasting type of conjunctivitis (inflammation of the eye’s thin lining, the conjunctiva). The word ligneous means ...
Light–near dissociation means your pupils don’t get smaller when a bright light shines in the eyes, but they do get smaller when you look at something close ...
Idiopathic Intracranial Hypertension means the pressure inside the skull (and around the brain and optic nerves) is too high even though scans do not show a ...
Every time you blink, a very thin strip of tissue on the inner edge of your upper eyelid acts like a tiny windshield wiper. It spreads tears smoothly across ...
Leukocoria literally means “white pupil.” Instead of the normal black opening in the center of the eye, you see a white, yellow-white, or grayish shine when ...
Leukemic optic neuropathy means the optic nerve—the cable that carries visual signals from your eye to your brain—is injured because of leukemia or its ...
Leprosy—also called Hansen’s disease—is a long-lasting bacterial infection that mainly attacks the skin and the peripheral nerves (the nerves outside the brain ...
Glaucoma is damage to the eye’s optic nerve caused by pressure inside the eye that is too high for that eye to tolerate. Lens-induced glaucoma happens when ...
Leigh syndrome (also called subacute necrotizing encephalomyelopathy) is a rare, serious brain disease that mostly begins in babies or young children. It ...
LeFort fractures are specific break patterns in the middle of the face (the “midface”). They were first mapped by a French surgeon, René Le Fort, who studied ...
Leber Hereditary Optic Neuropathy—usually shortened to LHON—is an inherited eye condition that mainly affects the optic nerve, the cable that connects your eye ...
LCA is a group of rare, inherited eye conditions that start at birth or soon after. The problem lives in the retina, the “camera sensor” at the back of the ...
Lattice degeneration is a thinning and weakening of the far-edge (peripheral) retina. Under a dilated eye exam, the thin patches look like narrow, criss-cross ...
Lattice corneal dystrophy is an inherited eye disease. “Inherited” means it is passed down in families through genes. It affects the cornea, the clear front ...
LASIK is laser eye surgery that reshapes the clear front window of the eye (the cornea) so light focuses properly on the retina. A very thin flap is made on ...
LASIK is laser eye surgery that reshapes the clear front window of the eye (the cornea) so you can see without glasses. A very thin flap is made on the ...
