PRK recommended procedure for U.S. Naval aviators

San Diego-U.S. Naval aviators can benefit from PRK in terms of restoration of visual acuity to 20/20 and enhanced flight performance, said David J. Tanzer, MD, surgical director, refractive surgery center, department of ophthalmology, Naval Medical Center, San Diego.

The mean preoperative refraction was about -3 D (range, +5.25 to -9.13 D). At 6 months after PRK, the mean refraction was plano (range, +3 to -3 D). At the 6-month mark, 85% were within ±0.5 D of intended correction and 96% were within ±1 D.

"By 6 months, 95% had an UCVA of 20/20 or better, 79% had reached 20/16 or better, and 50% had an UCVA of 20/12.5 or better," Dr. Tanzer said. "With the exception of one eye in one Naval Flight Officer, all patients achieved a best-corrected visual acuity (BCVA) of 20/20 at 3 months."

Return to flight status At 4 weeks postoperatively, 74% of naval aviators were able to resume flying duty. By 8 weeks after PRK, almost all (94%) were eligible for flight. By 3 months, all but two aviators could resume flight duties. To return to flight status, these criteria had to be met: 20/20 or better vision restored, either UCVA or BCVA refractive stability, no change >0.5 D in either sphere or cylinder over two exams separated by at least 2 weeks, no quality-of-vision complaints that may represent a safety-of-flight issue.

"By 6 weeks postoperatively, 90% of aviators were eligible to fly without visual correction, with both eyes achieving 20/20 or better uncorrected vision," Dr. Tanzer said. "The average time to return to flight status was 5.4 weeks."

From an operational perspective, more than 47,000 flight hours have been logged and more than 18,600 landings have occurred in aviators who received PRK, he said.

Evaluating flight performance All naval aviators completed a flight performance questionnaire, which included 34 aviation-related questions, before and at 2 and 6 months after the procedure.

Preoperatively, they were asked if their eyesight was impaired during a specific task. After surgery, they were asked if PRK had affected that specific task in terms of making it easier, harder, or no change, according to Dr. Tanzer.

More than half of the aviators (56%) noted that their vision under G-load had improved after PRK, and none thought it had worsened at 6 months postoperatively.

At 6 months after PRK, 78% said that their vision had improved for detecting aircraft and only 1% thought that it was worse.