SBK, PRK shown to have same biomechanical properties

CHICAGO — A study showed that sub-Bowman's keratomileusis and photorefractive keratectomy both have the same biomechanical properties, according to a surgeon speaking here.

Daniel S. Durrie

Daniel S. Durrie, MD, presented a study that involved 100 eyes of 50 patients at the annual meeting of the American Society of Cataract and Refractive Surgery.

"There's not a lot of ways in the clinic we can measure biomechanics of the cornea, so I did everything I could think of to try and answer that question," he said. "None of the tests we have so far ... show that PRK is better biomechanically than SBK."

Dr. Durrie said the two-site study looked at 50 patients who received alcohol-assisted PRK in one eye and SBK in the other, randomized to dominant eyes. Postoperatively, the study measured the ocular response, tonometry and wavefront changes.

In looking at these measurements, there was no difference between the biomechanical impacts of the two procedures, he said.

In a discussion with the session moderators after the presentation, Dr. Durrie said he has not seen any disadvantages in going thinner — the SBK patients received 100-µm flaps — or smaller — the patients received 8.5-mm flaps. Instead, he said he saw advantages for the thinner and smaller flaps he is using.

"As we have gone smaller, our dry eyes in our practices really dried up, so to speak," Dr. Durrie said. "We're cutting less fibers as we're going thinner and less fibers as we're going smaller. You do not have to do big flaps to do big ablations."

He said the information on dry eye rates was reviewed as part of this study, but it was not presented at the ASCRS meeting.