Keeping an Eye on Side Effects of Laser Eye Surgery
May 16, 2000 -- Tired of uncomfortable contact lenses? Annoyed by the
slip-sliding of glasses? You would consider laser eye surgery to correct your
vision, but you've heard there can be distracting side effects, like seeing
halos and starbursts around lights. How common are they, and which type of
surgery will give you the best results with the lowest risk of side effects? A
new study, in the May issue of the journal Ophthalmology, may help open
"The side effect that the study specifically focused on were these
optical symptoms that are not captured with conventional, 20/20 vision
testing," study co-author Roger Steinert, MD, tells WebMD. "When you go
on the Internet, you see lots of comments on halos and glare and [double
vision]. ... Those kind of visual complaints, we know they occur, and we hear
about them from patients. What this study looked at is whether or not there was
a difference between LASIK and PRK [two popular types of laser surgery] in the
frequency of these complaints." Steinert is a consultant for Summit
Technology Inc., which manufactures lasers for eye surgery.
Steinert and colleagues asked 220 patients with moderate to severe
nearsightedness to fill out a questionnaire about certain side effects they
experienced before and six months after undergoing one of two procedures: the
older PRK or the more recently approved LASIK.
In both procedures, the surgeon uses a laser, which produces a beam of
ultraviolet light in pulses that last only a few billionths of a second, to
remove a microscopic amount of tissue from part of the eye called the cornea.
"Basically, you are using the ... laser to reshape the cornea," Michael
Gordon, MD, tells WebMD. "They are both effective, but there is more
scarring and discomfort and greater delay in visual recovery associated with
In PRK, Gordon says, the doctor removes the top layer of cells, called the
epithelium. "Then you do the lasering and remodeling right on the surface
of the cornea. The reason you get a delay in visual recovery and some pain is
that removing the epithelial layer is like having a large scratch on the
surface of your cornea that has to heal over.
"With LASIK, the surface of the cornea is essentially untouched because
you make a little flap in the very upper layer of the cornea, then you do the
lasering and reshaping of the cornea underneath the flap," he says.
"The flap folds back and conforms to that new shape, so you don't have that
scratch that has to heal on the surface of the cornea." Gordon, who is in
private practice at the Vision Surgery and Laser Center in San Diego, was one
of the surgeons involved in the study.