Wavefront-guided ablations: superior to wavefront-optimized ablations?

Wavefront-guided ablations are superior to wavefront-optimized procedures and topography-guided ablations because wavefront-guided ablations truly customize the ablation, according to Michael Knorz, MD, professor of ophthalmology, University of Heidelberg, Mannheim, Germany.

“Wavefront-guided procedures minimize not just spherical aberration but all aberrations, provide the only way to truly customize the ablation, and provide the only way to perfectly align the laser treatment,” Dr. Knorz said.

He explained that with topography-guided ablations, the ablation is designed to achieve a “normal” corneal topography. Topography-guide ablation is very useful in highly aberrated corneas, for example, after a previous LASIK procedure.

“However, there is no information on the total aberrations of the eye and on refraction,” Dr. Knorz said.

In wavefront-optimized ablations, the ablation is designed to minimize induced spherical aberration. The prolate corneal shape is maintained.

“This is not a customized ablation as the spherical aberration of the eye is not measured,” he said.

Wavefront-guided procedures involve aberrometry, calculation of customized ablation, and iris registration, which compensates for cyclotorsion and pupil centroid shift.

“Wavefront-guided ablation is a customized ablation,” Dr. Knorz said. “Iris registration is possible with wavefront-guided procedures only.”

A comparison of wavefront-guided ablation, wavefront-optimized ablation, and standard ablation performed by Capt. Steven Schallhorn, MD, San Diego, indicated that optimized LASIK is clearly an improvement over the conventional procedure. The optimized procedure still induced more higher-order aberrations than wavefront-guided ablations, however, he said.

“Wavefront-guided LASIK is superior to wavefront-optimized LASIK,” Dr. Knorz concluded.