LASIK outcomes compared

Oct 01, 2010

Wavefront-guided LASIK and wavefront-optimized LASIK both produced similar results when compared head to head in two studies.

Wavefront-guided LASIK and wavefront-optimized LASIK both produced similar results when compared head to head in two studies presented by Edward E. Manche, MD, and Louis Probst, MD, both of whom discussed 3-month results. The wavefront-guided outcomes, however, were better overall.

This prospective study included 90 eyes of 45 patients. One eye of each patient was randomly assigned to one of the procedures and the contralateral eye was treated to the other procedure.

The wavefront-guided procedures were performed using a certain excimer laser (VISX STAR S4 CustomVue, Abbott Medical Optics [AMO]), and the wavefront-optimized procedures were performed with a 400-Hz excimer laser (Allegretto Wave Eye-Q, Alcon Laboratories).

All flaps were created using a 60-kHz femtosecond laser (IntraLase, AMO).

Both groups were similar preoperatively. The mean spherical equivalent (SE) was about 4.5 D of SE and about 1 D of cylinder. The HOAs did not differ significantly.

One month postoperatively, the myopia decreased to about –0.25 D in both groups. The total higher-order root mean square (RMS) values increased in both groups.

At 3 months, the SE was –0.19 D in both groups. In the group that underwent wavefront-guided LASIK, the total higher-order RMS value increased from 0.33 to 0.38 µm, and in the group that underwent wavefront-optimized LASIK from 0.34 to 0.41 µm, the latter of which was significant. The residual cylinder was lower in the group that underwent wavefront-guided LASIK compared with the group that underwent wavefront-optimized LASIK (+0.16 versus +0.23 D), also a significant difference. Coma increased in both groups.

"We found excellent predictability in both groups, with all eyes within 1 D of the intended correction at 3 months," said Dr. Manche, professor of ophthalmology and director of cornea and refractive surgery, Stanford University School of Medicine in Palo Alto, CA.

In the group that underwent wavefront-optimized LASIK and the group that underwent wavefront-guided LASIK, 87% and 96% of eyes, respectively, were within 0.5 D of the intended correction, he said.

Regarding UCVA, again, both groups did well. One day postoperatively, all eyes had 20/63 or better. More patients in the group that underwent wavefront-guided LASIK achieved 20/20 or better (90% versus 78%) 1 week postoperatively.

The group that underwent wavefront-guided LASIK fared better at the 20/16 or better level and the 20/12.5 level 1 week postoperatively, according to Dr. Manche.

Three months after surgery, all eyes achieved 20/40 or better. However, as seen previously at the higher visual acuity levels, the group that underwent wavefront-guided LASIK had results superior to the group that underwent wavefront-optimized LASIK.

Both procedures also were found to be safe. No patient lost more than one line of best-corrected visual acuity (BCVA) in either group. There also was a significant shift to the right with eyes gaining lines of BCVA in both groups. There was no difference in the 5% and 25% contrast acuities between the groups at 1 and 3 months.

"We had excellent safety in both groups," Dr. Manche said.

The predictability was better in the group that underwent wavefront-guided LASIK, he said.

HOAs were induced in both groups, but the degree of induction was significantly higher in the group that underwent wavefront-optimized LASIK. The group that underwent wavefront-guided LASIK had lower residual cylinder. There was no difference in the 5% and 25% contrast acuities, but there was significantly better UCVA in the group that underwent wavefront-guided LASIK at all time points, he said.