Speed of recovery after conventional PRK improves

August 15, 2006

San Francisco-Traditional PRK performed using a modern excimer laser provides early visual rehabilitation for most patients. The gap in the speed of visual recovery between surface ablation and LASIK seems to be narrowing.

San Francisco-Traditional PRK performed using a modern excimer laser provides early visual rehabilitation for most patients. The gap in the speed of visual recovery between surface ablation and LASIK seems to be narrowing.

While the initial experience with LASIK was positive, the current trend has been to return to surface ablation procedures, according to David Varssano, MD, who spoke at the annual meeting of the American Society of Cataract and Refractive Surgery.

"The excimer laser has improved with scanning small spot lasers with Gaussian energy distribution, eye trackers, tissue-saving algorithms, and wider treatment zones," said Dr. Varssano, director, cornea and external disease service, department of ophthalmology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.

In light of this, Dr. Varssano and colleagues assessed the visual recovery soon after conventional PRK was performed using a flying small spot laser. Their rationale was that the rapid visual recovery after LASIK is the primary advantage compared with PRK. All PRK procedures were performed using the Allegretto excimer laser system (WaveLight Laser Technologie AG) in a prospective, nonrandomized clinical trial. Two surgeons performed all simultaneous bilateral PRK procedures to correct myopia in patients who were targeted for emmetropia, he explained.

Eighty-one patients (162 eyes) were included in this study. The average patient age was about 30 years. The mean preoperative spherical equivalent was –3.0 D, which ranged up to –7.75 D. Cylinder ranged from 0 to 3.5 D. Most patients had a history of contact lens wear and all patients stopped wearing their contact lenses at least 1 week before undergoing PRK.

The main outcome measure of the study was the uncorrected visual acuity (UCVA) 1 week and 1 month after surgery. The secondary outcome measures were manifest refraction 1 week and 1 month after surgery, best spectacle-corrected visual acuity (BSCVA), manifest refraction, and haze 1 month after surgery.

"One-third of the eyes achieved 20/20 or better visual acuity 1 week after PRK, and two-thirds achieved 20/25 or better at the same time point. Ninety-five percent had 20/40 or better vision. Forty-four percent of the patients could see 20/20 with at least one eye; 80% could see 20/25; and 96% could drive," Dr. Varssano reported. "One month after PRK, the UCVA was good, with 80% of patients achieving 20/20 or better, 91% had 20/25 or better, and all patients had 20/40 or better."

The secondary outcome measures were very good. "The mean spherical equivalent 1 week after PRK was –0.11, and at 1 month it was –0.09. Mean astigmatism was 0.87 at 1 week and 0.54 at 1 month. The mean BSCVA at 1 month was 0.98. Haze (+1) developed in 12% of patients; many patients developed trace haze. The IOP was within normal limits in all patients.

"Based on these results, we concluded that traditional PRK performed using a modern excimer laser provides rapid visual rehabilitation for most patients, and the gap in speed of visual recovery between surface ablation and LASIK seems to be narrowing," Dr. Varssano stated.

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