LASIK Technique May End Halo Effect
Larger laser area may improve night vision problems
(HealthDay is the new name for HealthScoutNews.)
FRIDAY, July 25, 2003 (HealthDayNews) -- New research is offering encouraging news for patients at risk for developing night vision problems after having laser eye surgery.
Patients with large pupils sometimes begin to see halos around lights after undergoing the procedure. In a study released July 24, doctors tested a unique type of LASIK surgery designed for those patients and found the technique is "extremely safe and effective," says study co-author Dr. Brian S. Boxer Wachler, director of the Boxer Wachler Vision Institute in Beverly Hills, Calif.
Other experts say the findings are encouraging, but they point out that eye doctors can turn to other treatments to prevent night vision problems. The new study is actually quite limited because it only examined the safety of the procedure, says Dr. Vadim Filatov, a LASIK specialist based in Greenwich, Conn. "All they're saying is that they didn't make anything worse."
LASIK surgery has become a routine treatment for ordinary vision problems. Doctors make a small flap in the eye and use a laser to reshape the cornea, the clear layer that covers the front of the eye.
While LASIK is "extremely safe," Boxer Wachler says, the most common side effects are night vision problems. "If someone's going to complain of anything, they'll complain of halos around lights. When they're driving they'll see starbursts and halos around streetlights and car lights."
People with large pupils -- about half of those who undergo the procedure -- are most likely to encounter the night vision problems, Boxer Wachler says. At night, the pupils naturally become larger and expand beyond the area of the cornea that was reshaped by the laser, he says.
In essence, it's as if the patients are looking through two pairs of glasses at the same time -- one that provides excellent vision and one that does not. "You get a blur superimposed on top of the clear [view], and that's what the halo is," Boxer Wachler explains.
In the study, researchers tested a LASIK technique that expands the area that is reshaped by the laser beyond the typical limit of 6.5 millimeters. In the study, of 186 patients, the "optical zone" grew to as much as 8 millimeters.
The findings of the study appear in the July issue of Ophthalmology.
According to the researchers, the patients did well. "Now people can be treated with the large zones routinely and not have to worry about the halo problems," Boxer Wachler says.
Filatov, the Connecticut eye doctor, says the study results don't go quite that far. While they're important, they only prove the safety of the so-called "large-zone" technique, he says.
Patients with large pupils have a variety of options, says Dr. Cary M. Silverman, an ophthalmologist in East Hanover, N.J. Instead of "one-size-fits-all" LASIK treatments, doctors are now turning to surgeries that are customized for the eyes of individual patients, he explains.
"With the new treatments, you're going to get an improvement in night vision," Silverman says. "Patients might get some halos and a little bit of glare, but their satisfaction with their night vision should be improved."