Once upon a time — and for a very long time — bad eyesight meant wearing glasses. Then came contact lenses, hard and soft, which compensated for poor eyesight. They were followed by radial keratotomy and similar procedures that offered surgical corrections.
Now all those remedies can be avoided, at least during waking hours, with orthokeratology, a therapy in which the shape of the cornea is held in place by rigid contact lenses while the wearer sleeps.
"It’s kind of controlling the shape of the cornea," said Dr. Kristin Shimabukuro of Mid Pacific Eyecare, one of several eye-care clinics on Oahu that offers the therapy. "It has been shown to slow the progression of becoming even more nearsighted over the years."
The therapy, which the clinic calls vision shaping, is similar to a dentist putting braces on teeth to straighten them. A patient is fitted with a pair of customized contact lenses worn during sleep. The lenses keep the cornea from becoming too curved, a common cause of nearsightedness. The contact lenses are removed in the morning, and, if all goes well, the patient can function without lenses of any kind.
One major difference between vision shaping and dental braces, however, is that the patient will have to use the contact lenses for life, Shimabukuro said. If the patient stops wearing the lens, the cornea will return to its orignal distorted shape in one or two days, she said.
"It doesn’t eliminate them from having to go back to contact lenses (or eyeglasses)."
Orthokeratology is appropriate for people with mild to moderate nearsightedness, generally those with prescriptions of -5 (0 being perfect 20/20 vision) or less. It’s unsuitable for people with weaker eyesight — those unable to see the large "E" on eye charts — because the amount of correction needed is too great, Shimabukuro said.
Early diagnosis is key. For a 10-year-old patient, a diagnosis of -2 would be "a perfect candidate because they would only have to push on that cornea just a little bit," she said. However, Shimabukuro does have patients in their 30s and 40s who use the lenses.
Candace Lui, the daughter of Shimabukuro’s colleague Dr. Kevin Lui, has been wearing vision-shaping contact lenses since Christmas and is happy to have them.
"It was just easier for me in class because sometimes I would forget my glasses in my locker," said Candace, a 14-year-old freshman at Punahou School. "My friends who don’t have the ones you wear at night, I always hear them complaining because they have to go and fix (their contacts), like if they get dust under them."
Mid Pacific Eyecare, which has offices in Honolulu and Kailua, charges $1,725 for its vision shaping therapy, including testing, cost of the first set of lenses and follow-up, which involves four to six visits over a two-month period.
THE THEORY behind orthokeratology has been around for decades and was approved in Europe in the late 1980s. However, it didn’t become more widely prescribed until technological advances allowed for more accurate — and less invasive — mapping of the surface curvature of the cornea and more precise manufacturing techniques. Also crucial to more widespread use was the development of materials that provide higher levels of oxygen permeability in the lenses for overnight use.
The U.S. Food and Drug Administration approved orthokeratology for nightly use in 2002.
The custom-made lenses are slightly larger and thicker than normal hard contact lenses and require similar maintenance on a regular basis.
Patients who are already using contact lenses often need a few weeks to accustom themselves to using them.
"It’s going to feel like there’s something in your eye," Shimabukuro said.
Candace, who had never worn contact lenses of any kind before getting her overnight lenses, said it took her a couple of months to get used to them, but now "I just put them on, go to sleep."
ON THE NET:
» visionsource-midpacificeyecare.com
