The cornea, or clear covering at the front of your eye, has two important functions. It helps protect the other structures of your eye from foreign debris and helps focus light entering your eye.
The shape of your cornea determines how light is focused on the retina in the back of your eye. A normal, healthy cornea has a round shape like a dome, and focuses light directly on the retina. The retina receives the light, converts it into signals and transmits the signals to the brain for visual recognition.
Corneas that develop a degenerative disease called keratoconus thin and bulge abnormally, taking on a more cone-like shape. This irregularity is known as ectasia, and it interrupts the focusing of light rays, causing blurry, distorted vision that cannot be corrected with glasses or contact lenses.
The team at Vista Eye Specialists has special expertise in the management of corneal disorders, including keratoconus. We have seen particularly excellent results with scleral contact lenses and rigid gas permeable contact lenses. Corneal crosslinking, another treatment option, is available at our partner practices in northern Virginia and Richmond.
Keratoconus: Overview
Corneal Crosslinking for Keratoconus
Corneal crosslinking is designed to strengthen the collagen crosslinks in the inner layers of the cornea. Collagen fiber crosslinks function as structural support for the cornea, but corneas affected by keratoconus do not have adequate crosslinks.
Corneal crosslinking involves applying a combination of ultraviolet light and riboflavin drops to the eyes, causing new collagen crosslinks to develop. This stabilizes the cornea and prevents it from bulging further. The treatment itself can be performed at our office and takes approximately one hour.
2 Approaches to Corneal Crosslinking
There are two approaches to corneal crosslinking. In epithelium-off crosslinking, the outer layer of the cornea (called the epithelium) is removed so the riboflavin drops can soak into the deeper layers of the corneal tissue. In epithelium-on crosslinking, the outer layer of cells is left intact.
Corneal Crosslinking Recovery
After treatment, side effects like sensitivity to light or the sensation of a foreign body in the eye can occur. In epithelium-off crosslinking, there may be slightly more discomfort as the cornea heals. But these aftereffects are mild and temporary. Medicated eyedrops must be used after treatment to prevent infection and promote healing.
Corneal crosslinking works best in cases of mild to moderate keratoconus. It cannot cure the disease, but it can stop it from progressing. Some patients respond to a single corneal crosslinking treatment session, and others need several treatment sessions.
Post-LASIK Ectasia
Keratoconus is not the only factor that can cause corneal ectasia. Rarely, corneal ectasia can be a complication of laser eye surgery procedures like LASIK or PRK. In patients with naturally thin corneas, high myopia or irregular astigmatism, removing corneal tissue with a laser during LASIK or PRK weakens the cornea permanently. Luckily, corneal crosslinking can strengthen the corneas of patients affected by post-LASIK or post-PRK ectasia.
