Paragon Vision Sciences, a respected maker of the material used in rigid gas-permeable contact lenses, developed CRT. The lenses work by molding and flattening the cornea. The flatter cornea then focuses images farther back inside the eyeball, projecting them on the retina instead of in front of it, as is the case in nearsightedness. The lenses must be worn every night (or, for some patients, every second or third night) or the cornea reverts to its previous shape.
This constant corneal back and forth is one of the reasons some ophthalmologists, such as Ernest W. Kornmehl, a clinical instructor of ophthalmology at Harvard Medical School, don't like the product. "I can't imagine it's a good thing if the cornea is purposely being flattened, then going back, and being flattened, then going back," he says. He worries that CRT could permanently damage the cornea and lead to infection from wearing these lenses at night. The FDA study found no problems. But Dr. Schachar Tauber, an ophthalmologist and assistant professor at Yale University School of Medicine, notes that the study followed wearers for only nine months. Plus, Dr. Kornmehl says CRT doesn't work for some wearers.
The folks at Paragon admit they would like longer-term results. But that's a shortcoming of all new treatments, they say. The same concerns could have been raised about regular contact lenses and LASIK in their infancy, says Joe Sicari, president and chief executive of Paragon. Also, by now, some patients have been wearing Paragon CRT lenses for 3 1/2 years, Sicari points out, and, "there have been no reports of abnormality in any way, shape, or form."TURF WAR
Reticence on the part of ophthalmologists dates to bad experiences with a precursor treatment called orthokeratology, says Dr. Lisa G. Wohl, one of only two ophthalmologists in the Chicago area listed on Paragon Vision Sciences' Web site (paragoncrt.com) as certified to fit CRT lenses. But that was before gas-permeable lens materials and sophisticated eye-mapping equipment.
Also, she adds, the turf war between ophthalmologists, who perform LASIK, and optometrists, who can fit contacts and CRT lenses, may add to doctors' reluctance. "To be honest," says Dr. Wohl, "if I hadn't needed this myself, I probably wouldn't have been as receptive."
Now, both she and her husband (who were poor candidates for LASIK) wear Paragon CRT lenses. She thinks they are safer than either soft contact lenses or LASIK.
Until more studies are in, patients will have to decide which they fear more: surgery or night lenses. Or they can learn to love their corneas just the way they are. By Carol Marie Cropper