Map - Dot - Fingerprint Dystrophy
What is Map-Dot-Fingerprint Dystrophy?
Map-Dot-Fingerprint Dystrophy (also known as Epithelial Basement Membrane Dystrophy or simply EBMD, and Cogan's Dystrophy) is a disease that affects the top layer of cornea. It is commonly called Map-Dot-Fingerprint Dystrophy because of microscopic dot and fingerprint-like patterns that form within the layers of the cornea.
The cornea is comprised of five layers. EBMD affects the superficial corneal layer called the epithelium. The epithelial bottom, or basement layer of cells‚ becomes thickened and uneven. This weakens the bond between the cells and sometimes causes the epithelium to become loosened and slough off in areas. This problem is called corneal erosion.
Even though this disease is commonly known as a dystrophy (a term that describes genetic diseases), EBMD is not necessarily an inherited problem. It often affects both eyes and is typically diagnosed after the age of 30. Cogan's usually becomes progressively worse with age.
Signs and Symptoms
Most patients with EBMD have no symptoms at all. The symptoms among patients may vary widely in severity and include:
- Light sensitivity
- Fluctuating vision
- Blurred vision
- Irregular astigmatism (uneven corneal surface)
- Mild to extreme irritation and discomfort that is worse in the morning
Detection and Diagnosis
The doctor examines the corneal layers with a slit lamp microscope. In some cases, corneal topography (surface curvature map) may be needed to evaluate and monitor astigmatism (shape irregularity) resulting from the disease.
The treatment for EBMD is dependent on the severity of the problem. The first step is to lubricate the cornea with artificial tears to keep the surface smooth and comfortable. Lubricating ointments are recommended at bedtime so the eyes are more comfortable in the morning. Salt solution drops or ointments such as sodium chloride (Muro 128) nightly for several months are often prescribed to reduce swelling and improve vision. Gas permeable contact lenses are occasionally fitted for patients with irregular astigmatism to create a smooth, even corneal surface and improve vision.
For patients with recurrent corneal erosion, soft, bandage contact lenses may be used to keep the eye comfortable and allow the cornea to heal. In some cases, laser treatment may beneficial. The surgeon removes the epithelium with an Excimer laser (same laser used in LASIK surgery) to create a rough but regular surface (similar to sanding plank before painting). The epithelium quickly regenerates (similar to applying new paint), usually within a matter of days, forming a better bond with the underlying cell layer.