Lisbon, Portugal?The preliminary results from the ongoing FDA trials of a comparison of wavefront-guided and wavefront-optimized treatments with the Allegretto Excimer Laser (WaveLight Laser Technologie AG) indicate that the two treatments provide similar results, reported Karl G. Stonecipher, MD, at the European Society of Cataract and Refractive Surgeons annual meeting.
Dr. Stonecipher reported the results of the WaveLight FDA study that included 334 eyes that were followed for 3 months after treatment for myopia. Data collection was done by the clinical monitor Guy M. Kezirian, MD, FACS.
The study began in September 2004. One group of patients underwent wavefront-optimized treatment based on a phoropter or manifest refraction, and a second group underwent wavefront-guided treatments based on aberrometry. The patients had myopia that ranged up to 7.0 D and astigmatism up to 3.0 D.
"We obtained 20/20 or better visual acuity in both the wavefront-guided treatment group and the wavefront-optimized group at the 3-month examination with 95% and 94% reaching that target, respectively. The mean uncorrected visual acuity (UCVA) was 20/16 in 70% of the patients that underwent a wavefront-optimized treatment and in the group that underwent wavefront-guided treatment 62% of the patients reached that level of vision," he reported.
The postoperative mean spherical equivalent favored the wavefront-optimized treatment group, which may have resulted from a nomogram adjustment over the previous studies. The preoperative and postoperative evaluations of the best spectacle-corrected visual acuity (BSCVA) versus the UCVA were high at 83% in the wavefront-optimized group and 82% in the wavefront-guided group. There was no loss of BSCVA in either group.
Importance of RMSH
Dr. Stonecipher continued to emphasize the importance of the RMSH distribution; 81% of the eyes had an RMSH factor of less than 0.3 μm and in 96% of the eyes the RMSH was less than 0.4 μm. "When this is evaluated, the significance for the wavefront-guided group improved as the higher levels of root mean square were reached. However, the majority of the patients in both groups presented with a RMSH that did well with the wavefront-optimized profile," he explained.
"From this study it appears that only 5% to 10% of eyes may need a wavefront-guided treatment," he said.
"Excellent refractive predictability and visual outcomes can be obtained using wavefront-guided and wavefront-optimized treatments. In the absence of preoperative aberrations, results are similar for both treatments, but eyes with significant preoperative aberrations, such as coma and spherical aberration, may benefit from wavefront-guided treatments.