Laser eye surgery doesn't damage corneas, study suggests

While many people have undergone various vision-correction procedures in which laser light is used to reshape the cornea, there has been some people in and out of the medical profession who have worried the operations were causing damage that would eventually become apparent.

Seeking to determine if these concerns are justified, doctors at the Mayo Clinic in Rochester, Minn., set out to assess the risk to corneas posed by two popular laser vision-correction procedures, photorefractive keratectomy, or PRK, and laser in situ keratomileusis, better known as LASIK.

Two Mayo doctors, Sanjay V. Patel and William M. Bourne, studied 29 eyes of 16 patients who had undergone LASIK or PRK.

Photographs of the endothelial cells lining the corneas were taken and analyzed before and nine years after surgery.

What Patel and Bourne discovered and reported in an article published in the Archives of Ophthalmology was that after nine years the eyes that had been corrected with PRK or LASIK had experienced a 5.3 percent reduction in the density of corneal endothelial cells.

While that might sound bad it isn't, according to the doctors.

That's because on average the endothelial density loss recorded, about 0.6 percent per year, was the same in the eyes that had been laser corrected and those that had not.

"Our results support the findings of numerous short-term studies that found no significant endothelial cell loss after LASIK and PRK," the authors wrote in their Archives of Ophthalmology article.

Not only are their results good news for people who have undergone LASIK or PRK or considering it, according to Patel and Bourne, they suggest corneal tissue from organ donors who have had laser procedures could be used in a cornea transplant procedure known as posterior lamellar keratoplasty.

The Mayo Clinic study was supported by a grant from the National Institutes of Health, by Research to Prevent Blindness Inc., and by the Mayo Foundation.