Fuch's Dystrophy

Fuch's dystrophy is a slowly progressing disease that usually affects both eyes and is slightly more common in women than in men. Although doctors can often see early signs of Fuch's dystrophy in people in their 30s and 40s, the disease rarely affects vision until a person reaches their 50s and 60s.

Fuch's dystrophy occurs when endothelial cells gradually deteriorate without any apparent reason, such as trauma or inflammation. As more endothelial cells are lost over the years, the cornea becomes less efficient at pumping water out of the stroma. This causes the cornea to swell and to distort vision. Eventually, the epithelium also takes on water, resulting in great pain and severe visual impairment.

Epithelial swelling damages vision in two ways:

1. changing the cornea's normal curvature, and
2. causing a sight-impairing haze to appear in the tissue.

Epithelial swelling will also produce tiny blisters on the corneal surface. When the blisters burst, they are extremely painful.

The cornea is comprise of 3 layers of tissue as follows:

• Epithelium: As the cornea's outermost region--comprising about 10 percent of the tissue's thickness--the epithelium functions primarily to:
  1. block the passage of foreign material - such as dust or water - into the eye and other layers of the cornea, and
  2. provide a smooth surface that absorbs oxygen and other needed cell nutrients that are contained in tears.
  This layer, which is about five cells deep, is filled with thousands of tiny nerve endings that make the cornea extremely sensitive to pain when rubbed or scratched.
• Stroma: Located behind the epithelium, the stroma comprises about 90 percent of the cornea. It consists primarily of water (78 percent); layered protein fibers (16 percent) that give the cornea its strength, elasticity, and form; and cells that nourish it. The unique shape, arrangement, and spacing of the protein fibers are essential in producing the cornea's light-conducting transparency.
• Endothelium: This single layer of cells is located between the stroma and the aqueous humor. Because the stroma tends to absorb water, the endothelium's primary task is to pump excess water out of the stroma. Without this pumping action, the stroma would swell with water, become hazy, and ultimately opaque.

At first, a person with Fuch's dystrophy will awaken with blurred vision that will gradually clear during the day. This occurs because the cornea is normally thicker in the morning, and it retains fluids during sleep that evaporate in the tear film while we are awake. But as the disease worsens, this swelling will remain constant and reduce vision throughout the day.

When treating the disease, doctors will try first to reduce the swelling with ointments or soft contact lenses. They may also instruct a person to use a hair dryer, held at arm's length or directed across the face, to dry out the epithelial blisters. This can be done two or three times per day.

But when the disease makes even the most simple tasks hard to complete, a person may need to consider having a corneal transplant to restore sight. The short-term success rate of corneal transplantation is quite good for people with Fuch's dystrophy. But, some studies do suggest that the long-term survival of the donor cornea can be a problem.