Getting rid of glasses for good
The big promise of Lasik vision-correction surgery -- that you could throw away your glasses and contacts -- was only a half-truth, as maturing Lasik patients are beginning to realize.
Lasik has become hugely popular over the last decade, especially among young adults. But by middle age, virtually everyone develops presbyopia, the inability to read or focus close-up. So even former Lasik patients are rummaging through drugstore racks for a pair of reading glasses that won’t make them look like grandparents.
Soon, however, there may be a way for them to remain free of glasses. The Irvine company Refractec Inc. is studying whether conductive keratoplasty, a radio wave treatment for presbyopia, can be used on people who have had Lasik.
The idea is to pair the two treatments so people never have to wear contacts or glasses.
A preliminary study presented last month at the annual meeting of the American Academy of Ophthalmology in Chicago showed no safety problems and satisfactory outcomes for near and far vision.
“There were no patients who were dissatisfied. There was a significant improvement in near vision, and their distance vision was unaffected,” said Dr. Daniel S. Durrie, lead investigator of the study and an ophthalmologist in Kansas City.
“Patients are very interested in this. These are highly successful Lasik patients who say they’d really like to have a procedure [for presbyopia] that doesn’t cut or remove anything. And conductive keratoplasty is a very simple procedure.”
Eye doctors are eager to find options for aging Lasik patients. More than 4 million Americans have had Lasik; according to Refractec, the average Lasik patient is 39.
Lasik, which can be used for vision problems such as nearsightedness, farsightedness and astigmatism, uses a laser to reshape the cornea.
“People who had Lasik in their 30s, they got free of glasses and had this epiphany,” said Dr. Robert K. Maloney, director of the Maloney Vision Institute in Los Angeles, who performs Lasik as well as conductive keratoplasty. “All of a sudden, they are 45 and need reading glasses. These patients have spent five or 10 years without glasses. It’s depressive for that group.”
Conductive keratoplasty (Refractec calls its proprietary treatment NearVision CK) is a much different kind of treatment than Lasik. It is performed using a probe -- with a tip thinner than a strand of hair -- that releases radio-frequency energy.
The radio waves are applied to the cornea in a circular pattern to gently shrink small areas of collagen; this creates a constrictive band that increases the curvature of the cornea, bringing near vision back into focus.
NearVision CK was approved in 2002 for hyperopia, a condition that can occur in people of any age in which near vision isn’t clear. Last year, it was approved for the treatment of people whose only vision problem is age-related presbyopia.
The procedure has become the fastest-growing vision correction treatment since the introduction of Lasik in the mid-1990s.
In the study of 23 post-Lasik patients, Durrie found that 22 of them were able to read phonebook-sized print after conductive keratoplasty while maintaining good distance vision. There were no safety problems. The study eventually will encompass 150 patients.
If those patients show similar results, Refractec plans to seek approval from the Food and Drug Administration to market conductive keratoplasty for the treatment of presbyopia in post-Lasik patients.
“Most of us have been doing CK on post-Lasik patients for several years already. At present, it’s a legal and off-label use of the device,” said Dr. Marguerite McDonald, a clinical professor of ophthalmology at Tulane University School of Medicine in New Orleans. She served as an investigator of Lasik and was involved in earlier clinical trials for CK. “This study is designed to give doctors and patients more information about post-Lasik CK, and will allow the company to market for this indication.”
This combination of vision correction procedures won’t be for everyone, however. It works by producing monovision, meaning that one eye would be left as corrected by Lasik for distance, and the other would be corrected with CK to bring print and near objects into focus.
But this means the eyes can’t work together, and some people can’t adapt to having one eye blurred at all times. Depth perception can also be a problem with monovision.
But, McDonald said, monovision from conductive keratoplasty tends to be more satisfactory than that produced by wearing a single contact lens. Conductive keratoplasty interferes less with distance vision.
“A lot of people who ‘flunked’ monovision with contacts do well with CK,” she said.
Though conductive keratoplasty is fast and is considered extremely safe, another potential drawback is that it must be repeated periodically.
The aging eye’s lens continues to lose flexibility, so patients will need repeat procedures every one to four years at a cost of about $1,200 to $1,800 each time.
Former Lasik patients who develop presbyopia also can opt to undergo a Lasik “enhancement” in one eye to create monovision. That correction may be longer-lasting than CK. However, Maloney noted, there are more risks associated with Lasik, such as infection; dry eyes; debilitating vision symptoms, including hampered nighttime vision; and, in very rare cases, permanent vision loss.
However, future options for aging eyes are likely to be an improvement on monovision. For example, research is underway on a new laser software program that will correct presbyopia in both eyes.
“We’re very close to a way to program the laser so that our patients over 40 will be in focus at all distances with each eye: book distance, computer distance and infinity,” she said. “My guess is that this laser software will be approved in the U.S. within three years.”
Another rapidly evolving area of corrective eye surgery involves intraocular lens implants. Cataract patients who have a lens replaced have a growing number of options, including a lens that focuses for both distance and near vision.
Once that technology catches on among cataract patients, it’s likely to spread to older Americans who may be starting to develop a cataract but who also want to jettison their reading glasses, McDonald said.
“Intraocular lenses have been used to replace the natural lens for over 30 years, but only for cataract patients,” she said. “Now, cataract surgery has become so safe and effective that some people are opting to have their own natural lenses taken out and replaced with one of the new multi-focal intraocular lenses that allows them to see at all distances from each eye.”
An intraocular lens implant is a more invasive surgery than Lasik or conductive keratoplasty.
“What we really need,” said Maloney, “is to replace the natural lens of the eye with a lens that’s flexible. There is a lot of working going on with that.”
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Conductive keratoplasty uses radio waves to reshape the cornea, countering the effects of aging on the eye’s lens. The condition, called presbyopia, occurs as the lens hardens with age, resulting in blurred near vision. The CK procedure is done on one eye and takes about 3 minutes. It can be repeated as age continues to affect the lens.
How the procedure is done
1) A circular pattern is imprinted on one eye’s cornea with a temporary dye to guide the technician.
2) A radio-wave probe, with a tip thinner than a human hair, traces a circular line on the cornea.
3) The outward curve of the cornea is increased, improving the eye’s near vision.
How the procedure works
As presbyopia progresses, the eye’s lens loses flexibility and can’t adjust its focus on near objects. The radio energy of a CK procedure shrinks the corneal tissue in a “belt-tightening” effect. The adjusted curve on the cornea brings near objects into better focus, compensating for the less-flexible lens. The other eye’s cornea is not adjusted, so distance vision is not diminished.
Source: Florida Eye Institute