Corneal Diseases

The cornea is the outermost layer of the eye; it is a clear, dome-shaped surface that covers the front of the eye. The cornea has two functions: it helps shield the eyes from harmful materials, and it acts as the eye's lens. When light hits the cornea it refracts the incoming light onto the lens and refocuses the light on the retina. There are certain eye injuries or diseases that can affect the cornea and prevent you from seeing clearly including:

• Keratoconus
• Fuchs Dystrophy
• Pterygium
  

Keratoconus

Keratoconus is a common condition where the cornea progressively thins and bulges forward forming a cone shape. This condition is caused by certain factors including heredity, the constant rubbing of the eyes, or it could form as a result of other diseases.

The symptoms associated with Keratoconus are poor vision with occasional pain and tearing. The cone shape of the cornea may also produce astigmatism. These symptoms will usually develop at a young age and gradually become worse over time.

Keratoconus can be treated in the early stages with contact lenses or glasses. Generally the cornea will stabilize without causing any severe vision problems. If the eyes become scarred and contact lenses can be worn, a corneal transplant may need to be performed.

Fuchs Dystrophy

Fuchs Dystrophy is a slowly progressing disease that affects both eyes. It occurs when the endothelial (the inner most layer of the cornea) deteriorate. When this happens the endothelium is not able to pump water causing the cornea to swell, distorting vision. Epithelial swelling will damage the vision because it changes the cornea’s normal curvature.

The disease is generally treated with eye drops, ointments, or contact lenses to reduce the swelling in the eye. If these treatments do not work, and the disease begins to interfere with a person’s daily routine a corneal transplant to restore sight may be necessary.

Pterygium

A pterygium is a triangular tissue growth on the cornea. They are most common in warmer, sunnier climates, and among the 20-40 year old age group. Doctors believe that high exposure to ultraviolet light and dry conditions can increase the probability of the growth.

Symptoms associated with pterygium may include eye irritation, redness, and blurred vision. Because a pterygium grows slowly, it won’t affect your vision unless it is directly over the center of the cornea.

Because a pterygium is visible, most people want it removed for cosmetic reasons, however, even if it is removed, it can grow back. For this reason surgery to remove a pterygium is not recommended unless it is affecting vision.