Reshaping Your Eyes with Contact Lenses
When you sleep, you wear special contact lenses that gently reshape the surface of your eye, so you can see clearly even after you remove the lenses. The effect is temporary – generally enough to get you through a day or so, but you must wear the special lenses each night.Reshaping the cornea with contact lenses to improve vision isn’t new. Orthokeratology has been practiced by some eye doctors for decades. However, in the past ortho-k produced mixed results and wasn’t FDA-approved for overnight wear, so the procedure had limited appeal.
Then in June 2002, the FDA granted overnight wear approval to a type of corneal reshaping called Corneal Refractive Therapy (CRT). More overnight ortho-k approvals followed.
Myopia (nearsightedness) is caused by light coming into the eye in such a way that it doesn’t focus properly on the retina. Typically, this problem is corrected by using eyeglasses or regular contact lenses to re-focus the light rays.
A similar result can be achieved by reshaping your cornea. LASIK is a surgical way to do this. Ortho-k contact lenses flatten your cornea without surgery, enabling light to focus properly on your retina, resulting in better vision.
Orthokeratology is for people of any age who are nearsighted. The FDA has approved CRT for people with up to six diopters of myopia (-6.00 on your prescription); the VST approval is for up to five diopters. Astigmatism can also be treated: up to -1.75 with CRT, and -1.50 with VST. Many doctors believe the best candidates are people who have low amounts of myopia, about four diopters or less.
The procedures can be performed on practically anyone of any age, as long as their eyes are healthy. Ortho-k holds particular appeal for people who participate in sports, or who work in dusty, dirty environments that can cause problems for regular contact lenses.
Because ortho-k offers similar benefits to LASIK, it’s also appealing to adolescents and teens, who are not eligible for LASIK. However, there are some concerns about corneal infections in young people who have used ortho-k, so it’s wise to pursue this with an eye care practitioner who is experienced in treating this age group.
Eye care professionals usually aim for 20/20 vision, but 20/40 vision (the legal minimum for driving in most of the United States) is typically considered acceptable. In the FDA clinical study for approval of CRT, 93 percent of patients achieved 20/32 vision or better, and 67 percent achieved 20/20 or better. In the clinical study for FDA approval of one VST design, about 95 percent achieved 20/40 or better, and 73 percent achieved 20/20 or better. Both studies followed patients over at least a nine-month period.