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You may want to cite data from the military. After all, if refractive surgery is good enough for those who frequently serve in harm’s way, it should be good enough for the average office dweller. Increasingly, those studies show that LASIK surgery combined with the femtosecond laser is the preferred military modality.

 

“Femtosecond LASIK volumes will increase because of its ability to provide outstanding visual outcomes with a quicker return to duty,” said Philip F. Stanley, M.D., assistant in ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, who recently summarized the laser refractive surgery results that impact the U.S. military in the July 2008 issue of Current Opinion in Ophthalmology.

 

LASIK still isn’t approved for naval aviators, but it is for other U.S. military personnel and even U.S. astronauts.

 

Becoming a femtosecond soldier

Between 1987 and 1988, there were 85 naval aviators disqualified from flying because of poor distance vision, Dr. Stanley noted. “Returning to flight status requires 20/20 vision, refractive stability, and no quality of vision complaints,” he reported. That’s potentially disappointing for pilots who can’t meet those standards and costly for the military, which has to use ground trained personnel. PRK began to give hope to aviators previously disqualified.

 

In one study of PRK on 785 naval aviators, the average time to return to flight status was 5.38 weeks, and 90% of aviators were eligible to fly without correction by 6 weeks following surgery.
“Most importantly, there were no significant quality of vision complaints affecting safety of flight and 87% of pilots reported significantly better vision during carrier landings,” Dr. Stanley reported. “PRK is now a waiverable procedure for naval aviators.”

 

But PRK isn’t the perfect military vision solution. Clearly, it takes a matter of weeks for PRK to heal up to military standards. Corneal haze also reared its ugly head in a limited number of cases.

 

Researchers set out to see if LASIK could be a better alternative. The concern has revolved around the LASIK flap.

 

Investigators wondered whether ambient hypoxia and low relative humidity that might occur in a V-22 Osprey aircraft had any effect on post-LASIK corneas. They didn’t. Researchers wondered if prolonged exposure to high altitude affected these corneas. LASIK eyes experienced a +0.2 hyperopic shift, but untreated eyes had a very similar reaction.

 

LASIK eyes also have been exposed to air streams up to 400 mph at a variety of angles to simulate skydiving or ejection from a jet. “These air streams had no effect on the flaps other than a drying effect,” Dr. Stanley reported.

 

While LASIK safety in the military was being demonstrated, researchers also looked at efficacy. Much has been reported about the benefits of wavefront-guided LASIK over conventional modalities. But a study on wavefront-guided LASIK using mechanical microkeratomes versus the femtosecond laser helped make LASIK a waiverable procedure for U.S. military personnel, Dr. Stanley reported.

 

“Statistically significant findings were early foreign body sensation and photophobia with the femtosecond laser, but a faster visual recovery, improved contrast acuity, and a better quality of vision,” Dr. Stanley noted. “One week after surgery, 77% of femtosecond laser patients achieved an uncorrected visual acuity of at least 20/16 compared with 58% of mechanical microkeratome patients.” Clearly, LASIK’s visual recovery one week after surgery is a lot faster than PRK’s multiple weeks.

 

Night driving performance with wavefront-guided LASIK and femtosecond laser flap creation continued positive visual trends. “The average NDS [Night Driving Simulator] performance (identification, detection and glare) was significantly reduced after conventional LASIK and improved after wavefront-guided LASIK,” Dr. Stanley noted. “There was a significant loss in performance in 0-3% of wavefront-guided LASIK eyes versus 38-42% in conventional LASIK eyes. There was a significant improvement in 18-46% of wavefront-guided LASIK eyes versus 6-13% in conventional LASIK eyes.”

 

John D. Sheppard, M.D., professor of ophthalmology, microbiology, and immunology, Eastern Virginia Medical School, Norfolk, Va., suggested that PRK is fine for combatants, but it is time consuming to heal and there is a risk of haze.

 

But overall, there is better optics with the femtosecond laser and better healing time, he said.
The military is beginning to understand the benefits of LASIK’s “wow” factor, and perhaps your patients should, too.

 

Editors’ note: Dr. Stanley has no financial interests related to this report. Dr. Sheppard has no financial interests related to his comments.

 

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EyeWorld | by Matt Young EyeWorld Contributing Editor