Best of the best: femtosecond laser flaps and wavefront-guided LASIK

April 28, 2007

"Where naval aviators go, everyone else follows," said Capt. Steven Schallhorn, MD. Having said that, he traced the evolution of refractive surgery of naval aviators. Dr. Schallhorn, who delivered the Binkhorst Lecture, recently retired as director of the Cornea Service at the Naval Medical Center, San Diego.

"Where naval aviators go, everyone else follows," said Capt. Steven Schallhorn, MD. Having said that, he traced the evolution of refractive surgery of naval aviators. Dr. Schallhorn, who delivered the Binkhorst Lecture, recently retired as director of the Cornea Service at the Naval Medical Center, San Diego.

His investigations began with PRK in the 1990s with evaluations of contrast sensitivity and night-vision performance with goggles before and after PRK. Dr. Schallhorn and colleagues conducted a retention study of aviators to determine whether PRK was suitable for treating pilots who had refractive errors. A second study, an accessioning study, was also performed to determine whether patients who underwent PRK could perform well during flight training. As a result of these studies, PRK was found to be an acceptable procedure for aviators to undergo in order to attain the level of vision required to be aviators.

"These studies resulted in a profound change in visual standards required for aviators," Dr. Schallhorn said.

A major drawback with PRK was the prolonged time to recovery of vision, Dr. Schallhorn said. LASIK offered a faster visual recovery and thus a faster return to flying, less postoperative discomfort, and less chance of scarring.

When LASIK results were compared with those of PRK, LASIK was found to offer slightly lower vision than PRK. This led to studies of wavefront-guided LASIK, which resulted in a tighter distribution of spherical aberration with wavefront-guided procedures compared with standard LASIK procedures. Other research evaluated the differences between the flaps created with a microkeratome and those created with a femtosecond laser, the latter of which provided a better visual result. The overall conclusion of all the studies was that creating a flap with a femtosecond laser using a wavefront-guided LASIK procedure offers aviators the ultimate visual results.

"There is a huge benefit of refractive surgery for aviators," Dr. Schallhorn said. "Refractive surgery ushered in a new era in vision standard. Wavefront-guided LASIK offered the best of the best-the procedure is safe and effective and allows a fact return to flying."

The final frontier to evaluate is refractive surgery for astronauts and whether they might be able to undergo LASIK, he said.