Epithelial Basement Membrane Dystrophy (EBMD)

Epithelial Basement Membrane Dystrophy (EBMD)

Epithelial Basement Membrane Dystrophy (EBMD), is the most common of the corneal dystrophies. Ii is also known as Map-Dot-Fingerprint Dystrophy and Anterior Basement Membrane Dystrophy (ABMD), .

Since it was first described by Cogan et.al. in 1964, it is also known as Cogan’s Microcystic Corneal Dystrophy. The exact percentage of people who have it is not really known, since so many who have it are not symptomatic. The range is estimated to be 2-43% of the population, occurring more in women than in men. Most cases are considered degenerative in nature rather than hereditary.

The outer layer of the cornea, the epithelium, has as its foundation a basement membrane. EBMD is a condition in which the basement membrane is faulty, not allowing a strong adhesion to the epithelium. The membrane becomes thicker than normal and begins to protrude into the epithelium. Cells of the epithelium can break loose, causing painful erosions.

The name map-dot-fingerprint dystrophy refers to the changes in the cornea that can be seen when viewed with a slit lamp. The epithelium can have cloudy areas that resemble continents on a map, as well as opaque dots. The basement membrane can form lines that resemble small fingerprints.

Some of the symptoms of EBMD are sensitivity to light, the feeling that something is in the eye, and astigmatism (from the uneven corneal surface). Higher-order optical aberrations can also occur. These include glare, ghosting, blurriness, poor contrast, and poor night vision because of haloes and starbursts. Visual acuity can be adversely affected.

Sodium chloride drops/ointment or lubricating drops/ointment may help to alleviate symptoms. Sometimes, debridement of the cornea becomes necessary. A cornea specialist, preferably one with a specialty in ocular surfaces, is the best choice to perform this surgery. The epithelium is scraped off so it can replicate itself. Superficial keratectomy and diamond burr keratectomy are done manually; Phototherapeutic keratectomy (PTK) is done with a laser and is more expensive. The newest development is gentle debridement followed by placement of an amniotic membrane.

Numbing eye drops insure that these procedures are not painful. Moderate to severe pain can occur for 3-4 days afterwards, however. Since the cornea has 200-400 more nerve endings than the skin, it stands to reason that pain will result when they are exposed. Healing can take from 2-7 days, depending on the individual. After a couple of months, vision should be stable enough for new eyeglasses to be prescribed, if needed.

Unfortunately, there is no cure for EBMD. Corneal erosions can recur, making a repeat surgery necessary.

Sue Plaster is a Moderator, at Fuchs Friends, the Online Support Group of The Corneal Dystrophy Foundation
She resides in North Carolina