New Orleans—Separate prospective comparison studies of LASIK platforms have shown that the systems evaluated produced similarly successful outcomes with relatively minor differences. According to speakers at a refractive surgery session at the American Academy of Ophthalmology meeting, these studies also represent a welcome trend toward head-to-head comparisons of the various platforms and a step toward expanding evaluation criteria.
In the first study presented, a randomized, prospective, masked comparison of four excimer laser systems used in conventional LASIK, investigators found that all performed well with subtle differences in contrast acuity and refractive stability, said Steven C. Schallhorn, MD, director of cornea and refractive surgery, Naval Medical Center, San Diego.
However, there were differences in stability, contrast acuity, treatment diameter, ablation depth, and ergonomics, he added.
A nomogram adjustment group of 20 patients treated with each laser was evaluated at 1 month to determine whether the nomograms provided by the laser companies required adjustment. No adjustments were necessary, and these patients were included in the data analyzed for the study, Dr. Schallhorn said.
Subsequently, 400 additional patients were treated, 100 with each laser.
Dr. Schallhorn reported that a "glitch" occurred at this point in the study.
"Following completion of the treatments, an error was discovered. A minor, routine software upgrade altered the routine nomogram. One primary cohort had undercorrection by 8%. All laser companies were told of the situation but not which laser was involved. They all agreed to a redo of the primary cohort for the affected laser," he explained.