Dr William Boothe of Boothe Laser Center Discusses Keratoconus and Ectasia
Keratoconus and corneal ectasia are uncommon eye disorders in which a weakened cornea causes the eye to steepen and protrude into a cone-like shape. While the two disorders are very similar, keratoconus is a naturally occurring condition. Ectasia develops as an adverse side effect of refractive eye surgery.
Dr. William Boothe says that Keratoconus is a degenerative condition in which the cornea progressively thins out, causing the eye to bulge abnormally. People with keratoconus experience blurred or distorted vision and sensitivity to light, though the disease does not cause pain in the eye. Keratoconus often begins to develop during the patient’s adolescent years and grows worse into his or her 20s and 30s. In most cases, patients are diagnosed in the second eye several years after the first. Keratoconus affects roughly one in a thousand people and is the leading cause for corneal transplants.
Ectasia is a condition that resembles keratoconus but occurs as a direct post-operative effect of refractive eye surgery, usually LASIK surgery. Also referred to as keratecstasia, the condition happens when too much tissue is removed during the surgery, causing the collagen in the corneal tissue to weaken and the eye to flatten abnormally. Although the condition is rare and its causes are not fully understood, LASIK surgeons have begun to closely assess patient risk for ectasia during pre-operative testing. Patients with thin corneas are at greater risk for developing the condition after surgery.
Treatment Options
In most cases, rigid gas-permeable (RGP) contact lenses or specially designed lenses can improve vision for people with keratoconus or ecstasia—at least enough to enable them to read, drive and perform daily functions. Those who are intolerant of rigid lenses may try a “piggyback” lens, which combines an RGP lens on top of a soft lens to increase comfort. But in severe cases of keratoconus or ectasia, corneal transplants may be needed.
Studies are under way, however, to test the effects of corneal collagen cross-linking, a simple method that has been shown to strengthen corneal tissue and prevent the flattening of the cornea. The corneal tissue is made of numerous layers held together, or cross-linked, by a substance called collagen. The cross-linking method uses a combination of Riboflavin (vitamin B) and UV light to stimulate cross-linking of collagen fibers to strengthen the intrinsic properties of the cornea.
This treatment is not intended to cure the disease, but to slow and halt its progression, which could prevent the need for a corneal transplant. Contact lenses may still be needed to correct refractive error in the eye.
Cross-linking is already used widely around the world to treat such disorders but has not yet been approved for use in the United States. Researchers hope to get the emerging method of treatment approved shortly for use in the United States.
How It Works
Collagen cross-linking treatment is fairly simple and takes roughly 30 minutes. The patient is given a topical anesthetic and a small scratch is made on the surface of the eye. Riboflavin drops are applied to the eye, which is then exposed to UV light for roughly 30 minutes to activate cross-linking. After the procedure, an antibiotic is applied and the patient is provided with an eye pad to protect the eye while it heals.
For more information, please visit Boothe Laser Center for more information.