Jan. 17, 2002 COLUMBUS, Ohio -- Nearly a quarter to a third of patients that underwent LASIK surgery reported problems seeing at night, a new study suggests. Even so, 97 percent of the subjects said they would recommend LASIK to a friend.
Scientists at Ohio State University analyzed data from 605 patients who had undergone LASIK (laser-assisted in-situ keratomileusis) surgery at least six months earlier. Reported vision problems included seeing halos, starbursts and glare surrounding lights - problems that can affect the quality of vision at night.
The study showed that these symptoms may persist in some patients long after the eye heals. Such symptoms seemed to be linked to having had the surgery repeated, said Melissa Bailey, a study co-author and a postdoctoral fellow in vision science at Ohio State.
"Patients who had undergone the procedure again were generally less happy with the outcomes than those who had the surgery only once, although we're unsure why," she said.
Bailey presented the findings in December at the annual American Academy of Optometry meeting in Philadelphia. She conducted the research with statistician G. Lynn Mitchell and associate professor of optometry Karla Zadnik, both with the College of Optometry at Ohio State.
More than a million nearsighted Americans elected to undergo LASIK surgery last year in hopes of correcting their eyesight. But the researchers say that older patients, those with flatter corneas and those who needed to have the surgery redone were less likely to be happy with the results.
The researchers sent questionnaires to 605 patients, asking if they were satisfied with the surgery or if they had nighttime vision problems. They also examined the patients' medical charts. All subjects in the study had at least six months of recovery time.
"Doctors think that it takes about six months for a patient's prescription to stabilize," Bailey said. LASIK reshapes the cornea, the clear part at the front of the eye that filters light into the eye. During surgery, a surgeon cuts a flap across the cornea, leaving a "hinge" on one side. The surgeon then pulls the flap back, and uses a laser to shave cells from the cornea, thereby flattening it. The entire process usually takes only a few minutes.
The LASIK procedure used to correct for nearsightedness is very different from the procedure used to treat farsighted patients, Bailey said. The nearsighted eyeball is elongated, while the farsighted eyeball is shorter than normal.
Ninety-seven percent of the patients in the study said they would recommend LASIK to a friend, in spite of the side effects. Of the patients that would make the recommendation, on average, one out of four experienced some nighttime vision problems, compared to an average of two out of three patients who would not recommend the surgery.
Age seemed to predict who would and wouldn't be happy down the road. Patients in their mid-40s were less likely to say they would recommend LASIK to a friend, compared to patients in their early 40s. The average patient age was 42 years.
"Eyesight changes for most people when they hit their mid-40s," Bailey said. "They develop presbyopia - a form of farsightedness which usually means the person needs to start wearing reading glasses."
The researchers also found that patients with flatter corneas at the outset were more likely to see starbursts surrounding lights after surgery.
"The results suggest that corneal flatness is something that should be taken into consideration before a patient undergoes LASIK surgery, and only an optometrist or ophthalmologist can measure that flatness," Bailey said.
LASIK is the most common form of surgery used to correct nearsightedness, surpassing its predecessors radial keratotomy (RK) and photorefractive keratectomy (PRK). But doctors don't have a lot of information on the long-term outcomes of LASIK, which was approved by the Food and Drug Administration in 1998.
"We don't know if night vision problems continue indefinitely," Bailey said. "LASIK hasn't been around long enough or studied deeply enough. Many of the symptoms that occur right after surgery tend to disappear rather quickly.
"Patients need to remember that LASIK is an elective procedure," said Bailey, who advises those with doubts and questions about LASIK to consult an experienced surgeon.
"The technology is only going to get better - it's already a good procedure for most patients," she said. "Although we're just beginning to accumulate information on who will develop problems, we now have a starting point for further LASIK research."
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