April 18, 2006 (Press Release) -- Two popular laser-assisted
surgeries to correct nearsighted vision -
PRK - are equally effective at restoring 20/20 vision six months
to a year after the procedure, concludes a review of recent studies.
Both LASIK (laser-assisted in-situ keratomileusis) and PRK (photorefractive
keratectomy) use a laser to reshape the eye's cornea. PRK works
by shaving off microscopic layers of the cornea. In LASIK, a flap
is cut in the cornea in order to remove excess tissue below.
The review, published in the current issue of The Cochrane Library,
did find that people who have LASIK tend to recover their vision
faster and report less pain after surgery than PRK patients. However,
LASIK patients tend to be more uncomfortable during the actual surgery.
The authors reviewed six studies involving 417 eyes -- 201 treated
with PRK and 216 treated with LASIK. Some patients had surgery in
only one eye, and some had each eye treated with different procedures.
There was some evidence that a greater percentage of eyes treated
with PRK lose visual acuity six months after surgery, compared with
eyes treated with LASIK. This loss of vision after PRK may be partly
due to corneal "haze" caused by inflammation caused by the procedure.
"The risk of significant haze after PRK is an important difference
between these two procedures," review author Dr. Alex Schortt, of
the Moorefields Eye Hospital in London, England, said in a prepared
However, he noted that none of the studies in the review included
the use of an anti-scar drug called Mitomycin C, which has been
shown to be successful in reducing postoperative eye haze.