Epithelial Basement Membrane Dystrophy
What is a Corneal Dystrophy?
Generally speaking a corneal dystrophy is a non-infectious non-inflammatory gradual deterioration of one of the five layers of the cornea. We don’t fully understand why certain corneas become dystrophic but we do know that some dystrophies have strong hereditary inclinations are usually bilateral and that they can be progressive.
There is a variety of corneal dystrophies but the two most common are epithelial basement membrane dystrophy (EBMD) and endothelial cell dystrophy.
EBMD also known as map-dot-fingerprint dystrophy is by far the most common of the corneal dystrophies. EBMD generally occurs after the age of 40 but can first appear as late as age 70. The breakdown of the basement membrane in epithelial cell dystrophy can cause redness of the eye blurred vision light sensitivity and discomfort that can range from moderate irritation to severe pain. These symptoms are generally worse at the start of the day because sleep does not permit the blinking that keeps the surface of the cornea lubricated with tears.
EBMD received its nickname map-dot-fingerprint dystrophy because of its characteristic appearance under the examining microscope as an irregular pattern of cysts ridges and circular whorls resembling a map or a fingerprint. The cornea comprises five distinct tissue layers. The outermost layer -the epithelial cells - are fastened to an underlying basement membrane.
EBMD is usually not progressive but can be extremely variable in its presentation and can fluctuate in its course. The condition is typically bilateral but it can show up in just one eye. It also can be very asymmetric in its presentation often with a marked difference between the eyes.
The real problem with EBMD is that the basement membrane becomes thickened and irregular. The once-even layer of attached epithelial cells starts to buckle and break apart so that the cells are easily dislodged from the faulty underlying basement membrane (see link for recurrent corneal erosion). This loose attachment can result in the sloughing away of epithelial cells which triggers light sensitivity blurred vision and discomfort.
How is Epithelial Basement Membrane Dystrophy Treated?
Treatment for corneal epithelial cell dystrophy usually starts with efforts to augment the natural lubrication using artificial tears and hypertonic saline solutions just before sleep. Eye drops are also applied periodically during the day. In more severe conditions patients may have to wear a bandage contact lens to protect the corneal epithelium. Also measures to keep the home environment more humid using vaporizers or similar equipment may be recommended. If all these measures fail more permanent treatments include anterior corneal punctures to allow better adherence of cells; corneal scraping to remove eroded areas of the cornea and allow regeneration of healthy epithelial tissue; and the use of the excimer laser to remove surface irregularities.
Most cases of EBMD are easily managed and patients remain comfortable and abrasion-free. It’s important to stay in close contact with your doctor and to be diligent about following therapeutic instructions. With proper care painful loss of epithelial cells can be minimized or prevented leading to a decrease in the symptoms and discomfort associated with EBMD.