Within the past month the U.S. Food and Drug Administration has approved excimer laser surgery to correct astigmatism. Now many people who are nearsighted and suffer from astigmatism can have their eyesight corrected so they can see well without contacts or glasses.
On the other hand - or should that be, in the other eye? - hyperopia, or farsightedness, is not easily treated by scalpel or laser."There really has never been a very dependable, long-term, consistent treatment for hyperopia in any fashion so far by surgery," said Dr. Bryce G. Barker, an ophthalmologist with the IHC Salt Lake Clinic.
Advances in surgical correction of other vision disorders have been dramatic. Myopia (nearsightedness) can be fixed with two basic techniques: radial keratotomy (RK) and laser surgery. Now astigmatism, a vision distortion caused by a non-symmetrical cornea, is correctable, too.
Barker and a colleague, Dr. Roger P. Harrie, will be available from 10 a.m. to noon today to answer questions about eye care and vision improvement. They are the guest experts for Health Care Hotline, a free call-in program sponsored by the Deseret News and Intermountain Health Care.
In the recent past, RK was the standard surgical treatment to correct myopia. "It's advanced quite a bit, come a long ways, but there are still some inherent disadvantages to the surgery," Barker said.
With RK, a surgeon uses a diamond scalpel to make four to eight spoke-like cuts on the eye's cornea, the bulging surface over the lens. The cuts make the cornea flatten in the center, shortening the distance that light must travel and improving the focus on the retina, the light-sensitive material inside the eye.
The disadvantage is the cuts slightly weaken the eye's structural integrity, he said, making it a little more susceptible to trauma. If a person who had RK is punched in the eye or has an auto accident in which something strikes the eye, the cornea is a bit more likely to rupture, he said.
Another disadvantage of RK is that "it's not as powerful and cannot correct as much nearsightedness as the laser can," he said. Myopia of up to minus 31/2 diopters can be corrected by RK. On the other hand, the new laser surgery, technically called photorefractive keratectomy (PRK), can correct vision defects of up to minus seven diopters.
In PRK, the cornea isn't cut with slits. Instead, "the laser basically is used to remove microscopic amounts of the central cornea." That flattens the cornea by taking off "very fine layers," he said.
"The advantages (of PRK) are that it's much more powerful, it maintains the inherent structure of the eye, does not weaken the structure of the eye with regard to trauma," he said.
A problem of "creeping farsightedness" noted with RK patients may not happen, he said. However, PRK is such a recent development that it's possible not enough time has passed for that complication to surface.
PKR takes longer to heal and may be more uncomfortable during the healing process. Another disadvantage is it's about twice as expensive. RK costs $900 to $1,000 an eye, and PRK costs $1,800 to $2,000.
"Most of the time the insurance companies will not cover any of the refractive surgery procedures because they consider it elective, in the same vein as cosmetic surgery."
Another recent development is the invention of Laser Assisted Stromal In-situ Keratomileusis (LASIK) surgery. In LASIK, a small cutting device peels off a flap of the cornea, a computer-controlled laser sculpts the corneal bed, and the flap is replaced. The surgery heals quickly, and the patient's vision is much improved.
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ADDITIONAL INFORMATION
Call hotline today
Today's session of Health Care Hotline features two specialists in eye care.
Dr. Roger P. Harrie and Dr. Bryce G. Barker, both of whom are ophthalmologists with Intermountain Health Care and on the medical staff of LDS Hospital, will answer questions called in to the hotline's toll-free number. They can be reached from 10 a.m. until noon at 1-800-925-8177.
The free hotline service is sponsored by the Deseret News and IHC.