Study results tend to favor WFG for hyperopic LASIK

March 28, 2012

Early results from a pilot study comparing wavefront-guided (WFG) and wavefront-optimized (WFO) techniques for hyperopic LASIK show excellent safety and predictability for both, but also some differences between groups that consistently favor the WFG procedure, reported co-investigators Anthony C. Liu, MD, and Edward E. Manche, MD.

Stanford, CA-Early results from a pilot study comparing wavefront-guided (WFG) and wavefront-optimized (WFO) techniques for hyperopic LASIK show excellent safety and predictability for both, but also some differences between groups that consistently favor the WFG procedure, reported co-investigators Anthony C. Liu, MD, and Edward E. Manche, MD.

Dr. Liu is a resident, Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA. He presented analyses of data collected through follow-up to 6 months for 22 eyes of 11 patients who underwent WFG LASIK in one eye using the VISX S4 CustomVue excimer laser system (Abbott Medical Optics) and WFO LASIK in the contralateral eye with the Allegretto Wave EyeQ 400 Hz excimer laser (Alcon). All flaps were created with the same 60-kHz femtosecond laser (IntraLase, Abbott Medical Optics) that was programmed for 105 μm depth, 9.0 mm diameter, and a superior hinge. Dr. Manche, cornea and refractive surgery, and professor of ophthalmology, Stanford University School of Medicine, performed all of the surgeries.

“A small sample size is a significant limitation of our study, and because of the small patient numbers, we did not feel it was legitimate to perform statistical analyses of the data. However, we wanted to give a flavor for the outcomes as the data emerged, and the results show some noticeable trends,” said Dr. Liu. “Now we are enrolling more subjects and performing longer follow-up.”

The patients included in the prospective, contralateral eye comparison study had a mean age of 53 years and a mean preoperative MRSE of about +1.9 D in both eyes. Mean preoperative total HOA was about 0.35 μm. Eyes were randomly assigned to procedure by ocular dominance.

Data on MRSE outcomes showed predictability was excellent in both groups, with all eyes achieving refraction within 1 D of the attempted correction at 1, 3, and 6 months after surgery and ≥88% being ±0.5 D. Corresponding with the predictability data, UCVA outcomes were also similarly excellent after both procedures. UCVA was 20/40 or better in all eyes at 1 day after surgery and 20/50 or better in all eyes at 1 week and 1 month. At 3 and 6 months, UCVA was 20/32 or better in all eyes in both groups, and nearly half of the eyes in both the WFG and WFO eyes group see 20/12.5 or better unaided.

However, eyes that underwent the WFG procedure had less residual cylinder than the WFO group. At 1 month after surgery, mean manifest cylinder was +0.25 D in the WFG eyes and +0.45 D in the WFO group. At 6 months (9 patients), mean manifest cylinder was +0.14 D for the WFG eyes and +0.33 D for the WFO group.

In addition, the WFG procedure was more effective than WFO LASIK for reducing total HOAs. This difference was seen at 1 month and persisted at the 3- and 6-month follow-up visits.

In quality of vision analysis, only eyes that had the WFG procedure benefited with any gain in 5% contrast BSCVA (~25% at 3 months and ~45% at 6 months). There were no significant differences between groups in 25% contrast BSCVA at 3 or 6 months.

After 1, 3, and 6 months, about 10% of eyes in each group lost 2 lines of BSCVA. However, there was no difference between groups in safety outcomes and no eyes lost more than 2 lines of BSCVA at follow-up through 6 months.

Patients were also administered a questionnaire that asked if they had any preference for their vision in one eye. Among those who felt both eyes were not the same, a higher proportion favored the WFG eye over the WFO eye, ~60% versus 40%, and this split was constant at 1, 3, and 6 months.

Dr. Liu has no financial interest in the material he presented. Dr. Manche serves as an unpaid member of the medical advisory board for Abbott Medical Optics.

For more articles in this issue of Ophthalmology Times eReport, click here.

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