Soft Contacts for Cone-Shaped Corneas Could Eliminate Transplants
University of Rochester (New York) researchers have developed custom- designed contacts for people with keratoconic eyes, which are rare but disabling. From the side, the eyes look more pointed or cone-shaped than round. The condition causes people to see halos, and double and triple images. About 1 in 2,000 people suffer from the disease, usually in both eyes. The contacts would offer hope of nonsurgical treatment instead of corneal transplants.
“The condition shows up in a relatively small population, but it causes huge optical problems,” according to Geunyoung Yoon, assistant professor. “These people have problems so severe, they can’t tolerate glasses. The only available treatment is to wear hard contact lenses or a corneal transplant with a donored cornea if the disease is severe. And with the corneal transplant, there is a rejection rate.”
Conventional soft contacts do not work for keratoconic eyes, as they merely conform to the conical cornea shape. The custom-designed lenses have irregular front surface profiles designed to correct for specific aberrations of the cornea and crystalline lens. The scientists designed the front profiles by measuring with wavefront sensors exactly how light enters the subjects’ eyes through the misshapen cornea. Keeping the lenses exactly in place is still a challenge, as blinking notoriously shifts contacts.
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