Corneal Disease and Treatment

The cornea is the clear front window of the eye. It transmits light to the interior of the eye allowing us to see clearly. Corneal disease is a serious condition that can cause clouding, distortion, and eventually blindness. There are many types of corneal disease. The three major types are keratoconus, Fuchs’ endothelial dystrophy, and bullous keratopathy.

Keratoconus is a weakening and thinning of the central cornea. The cornea develops a cone-shaped deformity. Progression can be rapid, gradual, or intermittent. Keratoconus usually occurs in both eyes, but can occur in only one eye.

Fuchs’ endothelial dystrophy is a hereditary abnormality of the inner cell layer of the cornea called the endothelium. The purpose of this layer is to pump fluids out of the cornea, keeping it thin and crystal clear. When the endothelium is not healthy, fluids are not pumped out and the cornea develops swelling, causing it to become cloudy and decrease vision.

Bullous keratopathy is a condition in which the cornea becomes permanently swollen. This occurs because the inner layer of the cornea, the endothelium, has been damaged and is no longer pumping fluids out of the tissue.

With keratoconus, as the cornea protrudes or steepens, vision becomes increasingly blurred and contact lens wear, which is often an early treatment for the disease, becomes difficult. The contact lens may not stay on the eye due to the irregular shape of the cornea.

A person with Fuchs’ endothelial dystrophy or bullous keratopathy may first notice glare with lights at night or in bright sunlight. As these conditions progress, vision may be foggy or blurry in the morning and clear up as the day progresses. As the diseases further progress, vision will stay foggy later into the day and eventually may not clear at all.

• The cause of keratoconus in most patients is unknown
• Bacterial, fungal and viral infections
• Aging processes can affect the clarity and health of the cornea
• Bullous keratopathy occurs in a very small percentage of patients following cataract and intraocular lens implant surgery
• Heredity
• Contact lenses
• Eye trauma
• A variety of congenital and systemic diseases may affect the cornea

Many corneal issues can be treated with prescription eye drops or oral medications. For more advanced corneal disease, laser treatments, in office procedures, crosslinking, or transplant surgery may be necessary.

As with any serious eye infection, corneal disease should be treated immediately. Although a corneal transplant may be necessary to restore vision when the cornea becomes clouded, there are other measures that can be taken to prolong vision in the early stages of disease.

You should arrive at the St. Cloud Eye Clinic 30 to 60 minutes prior to your procedure. Once you have checked in, you may be offered a sedative to help you relax. You will then be prepared for surgery. The area around your eyes will be cleaned and a sterile drape may be applied around your eye. Your eye will be numbed with topical or local anesthetics. When your eye is completely numb, an eyelid holder will be placed between your eyelids to keep you from blinking during the procedure.

The most common type of cornea transplant at St. Cloud Eye Clinic is a Descemet Membrane Endothelial Keratoplasty (DMEK). During this surgery, the diseased endothelium is removed and replaced with a then disc of healthy endothelium from a donor cornea. This endothelium is held in place using a gas bubble at the time of surgery. This surgery takes approximately 30 minutes and you will need to lay on your back for the first few days, except for short breaks to eat and use the restroom.

Everyone heals differently, but most patients resume activities within a few days. Strenuous activity such as lifting, bending, or straining should be avoided for several weeks. To protect your eyes from inadvertent trauma, you will be advised to wear shields, glasses, or sunglasses while your eye heals.

The healing process can take months, but many patients begin to see well in the first few weeks. Steroid eye drops will be used to make sure the transplant heals properly and are typically continued for years to prevent your body from attacking the new cornea.

Realistic Expectations

Return of best vision after corneal transplant surgery may be recognized in three or four months for some, while it may take up to a year after the operation for others. As in any kind of transplant, rejection of the donated tissue can occur. The major signs of rejection are redness of the eye or worsening of vision. Rejection of a donor cornea is rare, but it is very important to contact your eye doctor immediately if the signs of rejection occur.

The success rate for corneal transplants depends on the cause of the clouding. For example, corneal transplants for degeneration following cataract surgery and those for keratoconus both have high success rates, while corneal transplants for chemical burns have lower success rates.

If you decide that a corneal transplant is an option for you, you will be given additional information that will allow you to make an informed decision about whether to proceed. Be sure you have all your questions answered to your satisfaction.