Farsighted People Can Now Set Their Sight On Non-invasive Laser Correction
So you just celebrated your 40th birthday. Funny how so many birthday cards harped on bifocal glasses and poor eyesight. Unfortunately, there is sobering truth behind the humor.
Farsightedness, or hyperopia, often manifests or progresses around age 40, says Tony Zacchei, M.D., a Wilmington, Del., ophthalmologist. Farsighted people have difficulty seeing objects at a distance and close-up.
If you're farsighted, you're in good company -- there are about 77 million hyperopic Americans versus about 75 million nearsighted Americans.
Until recently, correcting farsightedness involved glasses, contact lenses, or laser-assisted in situ keratomileusis (LASIK), an outpatient procedure in which the doctor uses an excimer laser to reshape the cornea.
Now there is laser thermal keratoplasty (LTK) approved by the Food and Drug Administration in June. Unlike LASIK, LTK is a non-contact technique -- no object touches the eye. And it's fast. In about five seconds, the physician can correct both eyes with laser-generated heat.
"I love the procedure – it's amazing," says Sandra Belmont, M.D., director of Laser Vision Correction Center at the New York Weill Cornell Medical Center. Belmont was an investigator for the LTK U.S. clinical trials.
Yet LTK only corrects mild-to-moderate farsightedness, +0.75 to +2.50 diopters. What's more, the solution may be temporary and some patients may still need reading glasses.
The procedure is only available to patients age 40 and up. That is because younger farsighted patients' eyes can auto-focus on objects, Belmont explains. They may not even need glasses. But the auto-focusing ability diminishes over time.
"As they get into their late 30s and 40s, they lose the ability to see first up close and then at a distance," she says.
The curvature of cornea, the eye's main focusing element, must stay a certain shape to offer clear vision. LTK restores the proper curvature.
Here is how it works. In the doctor's office, the patient sits upright in an examining chair. After inserting anesthetic drops in the patient's eyes, the physician inserts a retainer to prop open the eyelids.
The patient focuses on a yellow light, while the doctor uses a holmium YAG laser to heat the collagen around the cornea. Only the laser energy hits the eye; there are no incisions. As the collagen cools, it shrinks and changes the cornea's shape, improving the eye's focusing power.
"The wow factor is that you sit back from the laser and patients who have never been able to see their watch without their glasses can suddenly see what time it is," says Stephen Weinstock, M.D., an ophthalmologist who performs LTK in his Largo, Fla., office.
Patients' eyes may feel scratchy for about 24 hours, Zacchei says. Some may experience light sensitivity. Most patients recover quickly.
"This technology is the safest refractive procedure," Belmont says. "No one has gone blind. No one has lost vision. I've never seen an infection. There's been no substantial glare or halo effects."
LTK won't halt aging, however. As we get older, we develop presbyopia, in which the eye muscle loses its elasticity. It is hard to focus on objects close up or read. Even patients with successful LTK surgery may still require reading glasses.
One option is monovision. "You can correct one eye for distance and overcorrect the other eye, which would make it nearsighted," Weinstock explains.
He advises patients to simulate the effect with contact lenses or glasses first to see if they can adjust.
Like a face lift, LTK's effects will lessen over time, Zacchei says. "There is regression in every type of procedure that treats farsightedness," he says.
After six months, regression curves from LTK were either equal to or less than those following LASIK hyperopic surgery, studies report. Regression, however, does not mean vision will spiral back to its pre-procedure state.
"The advantage of LTK is that it's so easy and safe, you can repeat it," Zacchei says. "With other things it's a much bigger deal."
Is LTK right for you? You must have healthy eyes. People with corneal disease or autoimmune disease are poor candidates. What's more, your vision must be stable for six months. Your prescription cannot have changed during that time period. Pregnant women, for instance, often experience vision fluctuations.
LTK is deemed ok for those with an astigmatism less than or equal to 0.75 diopters. With astigmatism over this amount, people won't see significant results, Weinstock says.
Like other refractive surgeries, LTK generally is not covered by insurance. Prices range from $800 to $22,200 an eye. Some doctors offer payment plans.
Currently, Sunrise Technologies -- the Freemont, Ca, company that developed and patented the Hyperion LTK System -- is conducting U.S. clinical trials for treatments that correct hyperopia in the +1.25 to +5.625 range.
The future looks bright for LTK, Belmont says.
"I think it will be the procedure of choice to treat low-to-moderate farsightedness," she concludes. "And if it is approved to treat +5.625, it will outdistance all the other farsighted treatments."