The purpose of the inner layer or the endothelium of the cornea is to pump the fluid out of the cornea and keep it clear. When the endothelial cells stop working, the cornea swells; this is called corneal edema. The endothelial cells can be damaged in different ways—by surgical trauma, disease of the inner cell layer, trauma to the eye, certain types of glaucoma, some infections and contact lens over-wear. There are several treatments that eye doctors can use to treat cornea edema. The specific treatment depends on the reason for the edema and the severity of the condition.
Treatment of Other Conditions
If the corneal edema is caused by an underlying disease, treatment of that condition might improve or completely resolve the corneal edema. Some types of infections like herpes simplex stromal keratitis can cause corneal edema, and the use of corticosteroid eyedrops can resolve the edema while treating the infection. Using antibiotics to treat an infection can resolve any corneal edema associated with the condition. If a patient has a cloudy cornea from elevated eye pressure, lowering of the eye pressure with glaucoma medications will cause the edema to decrease.
Hypertonic Medications
Hypertonic solutions—solutions that have a high concentration of one substance compared to the other substance in the solution—can be used to pull the moisture out of the cornea to temporarily treat the edema. Hypertonic solutions such as Muro 128 ointment are available over the counter. These solutions are most helpful early in the disease process. Once the underlying disease has progressed, these solutions will be unable to clear the cornea.
Bandage Contact Lens
Sometimes in corneal edema, the corneal epithelium develops blisters. This condition is called bullous keratopathy. This condition is painful, and the eye doctor may place a soft bandage contact lens on the affected cornea to alleviate some of the discomfort. Since extended-wear contact lenses can increase the risk of corneal ulcer, this should be taken into consideration when deciding on the use of a contact lens. If corneal transplant surgery is an option, a bandage contact lens would not be used for very long.
Temporary Surgical Procedures
There are surgical procedures that eye doctors may perform in patients with corneal edema for whom corneal transplant is not an option. Different laser procedures can be used to improve pain symptoms by decreasing the formation of the blisters in bullous keratopathy. Another method of improving the symptoms of advanced corneal edema is to graft tissue over the cornea. Conjunctiva is often used for this purpose.
Corneal Transplant
Corneal transplant is the curative treatment for corneal edema. One form of corneal transplant is penetrating keratoplasty in which a segment in the center of the cornea is replaced with donor tissue. There is a risk of rejection with this procedure; the patient would need to use eyedrops for a period of time during the healing period. Some surgeons replace only the endothelial layer of cells with donor cells. This is a newer procedure but can be effective in resolving corneal edema.
References
- University of Maryland Medical Center: Cloudy Cornea
- Richmond Eye Associates: Corneal Edema
- "Cornea, Volume 1"; Jay H. Krachmer, Mark J. Mannis, Edward J. Holland; 2005
- University of Washington: Treatment Options for Corneal Edema
