Keratoconus is a progressive eye disease in which the normally round cornea thins and begins to bulge into a cone-like shape.
The cornea is the clear, central part of the surface of the eye. With keratoconus, the cone-shaped cornea deflects light, causing distorted vision.
Although many theories have been proposed, there is no definite known cause of keratoconus. Possible causes include genetics, a collagen deficiency, overexposure to ultraviolet (UV) rays from the sun, or excessive eye-rubbing.
Sign and Symptoms
Keratoconus often begins to develop in the teen years to the early 20s, although it can develop at any age. Changes in the shape of the cornea occur gradually, usually over several years. In most patients with keratoconus, both eyes eventually become affected.
Keratoconus can be difficult to detect because it usually develops very slowly. Signs of keratoconus may include:
- Distorted and blurred vision
- Myopia (nearsightedness)
- Double vision
- Headaches due to eye strain
- Light sensitivity
Your doctor will measure the curvature of your cornea to determine whether these symptoms are a result of keratoconus.
In the early stages of keratoconus, glasses or soft contact lenses may help to correct the nearsightedness and astigmatism associated with the disease. As the condition progresses and the cornea becomes increasingly thin, more advanced treatment is required.
Rigid Gas-Permeable Contact Lenses
If eyeglasses or regular soft contact lenses cannot control keratoconus, rigid gas-permeable (RGP) contact lenses are usually the preferred treatment. The rigid lens covers the cornea, replacing the cornea’s irregular shape with a smooth, uniform refracting surface, improving vision
Collagen Cross-Linking with Riboflavin (CXL, C3R)
Collagen cross-linking is a relatively new method for treating keratoconus. This procedure strengthens the cornea to slow or halt progression of keratoconus. It works by creating more chemical “links” or “bonds” within and between collagen fibrils, making the cornea more resistant to deformation.
This procedure involves painlessly removing some of the corneal surface (the epithelium) and applying riboflavin (Vitamin B2) drops for 30 minutes. Then a measured dosage of ultraviolet light is applied to the cornea for 30 minutes. A soft contact lens is applied during the initial four day healing phase and drops are used to help with healing and comfort. Vision may be a little blurry for the first two – three weeks as the eye completely settles.
Corneal Transplant Surgery
Surgery is needed for patients with advanced keratoconus, where other therapies no longer provide clear vision. This usually occurs in 15-20% of cases. In corneal transplant surgery, most of the cornea is removed and then replaced with a new donor cornea.