Strengthening Eye Collagen Fixes 2 Vision Disorders

Posted by Admin on February 27, 2009
Two little-known but related eye conditions, one stemming from LASIK vision-correction surgery, plunge sufferers into a world of blurriness and sensitivity to glare and light. But a novel development involving treatment with vitamin B2 drops and ultraviolet light, already approved in Europe, helps sufferers' vision improve. The conditions, known as keratoconus and iatrogenic keratoconus (or ectasia), affect about one in 2,000 people. They are characterized by a weakening of the thin, transparent film (the cornea) on the surface of the middle of the eye, which eventually results in a cone-like bulge, progressively destroying vision. Corneal transplants used to be the only effective remedy, and the two disorders account for 15 percent of them.

Ectasia is caused by LASIK surgery, and usually develops within the first two years after the procedure. "These [ectasia sufferers] are people who had a propensity to develop keratoconus probably, and simply developed it quicker or perhaps when they might not have developed it otherwise after they had LASIK," said Doyle Stulting, an ophthalmologist at Emory University Eye Center in Atlanta, Ga.

LASIK surgery employs a laser to sculpt the cornea in order to correct vision abnormalities, but the cornea is occasionally excessively thinned and damaged, promoting ectasia. The new treatment for the two disorders is known as collagen crosslinking (CXL). Collagen, a protein present throughout the body that promotes stiffness in tissues, has been found to become stronger in the cornea through greater molecular crosslinking upon exposure to riboflavin (vitamin B2) drops and UV light.

The procedure takes only a half-hour in the doctor's office. While it's still being studied in the United States, initial results show that CXL efficiently stabilizes eyes. International clinical trials have found similar evidence. And, since follow-up was done on some European patients for as long as eight years after CXL, the effects seem to be long-term.

 "As we move forward, I can envision a day where we will diagnose keratoconus very early, as soon as there are any abnormalities in the shape of the cornea," Stulting said. "We will crosslink those eyes, and then they won't progress." Patients identified as being prone to keratoconus who want to undergo a LASIK surgery can then receive a CXL treatment to strengthen their corneas in preparation for vision correction.

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