Treating LASIK-Induced Aberrations

Treating LASIK-Induced Aberrations

A decade of success in refractive surgery for myopia has produced an inevitable outcome: exceedingly high expectations. Indeed, 20/20 is no longer good enough, noted Ronald R. Krueger, MD. Night vision symptoms—glare, halos, loss of BCVA and double vision—can turn a patient from “20/ happy to 20/ unhappy,” added Scott M. MacRae, MD, professor of ophthalmology at the University of Rochester in New York. Before wavefront-driven custom ablation, outcomes of plano and 20/20 were the industry standard, and “there was nothing we could do or measure if our patients weren’t happy with that,” said Dr. Krueger, medical director of refractive surgery at the Cleveland Clinic’s Cole Eye Institute. “However, we now can identify any higher-order aberrations that a LASIK procedure may have induced. Now the question becomes whether we can treat these aberrations.” The Culprit: Conventional LASIK Traditional LASIK may be most responsible for induced aberrations. According to Dr. Krueger, “spherical aberration can increase by more than 100 percent —and coma and other aberrations by more than 50 percent—after conventional techniques.” With conventional myopic refractive surgery, just the act of making the cornea flatter in the center creates spherical aberrations, he said. Additionally, with traditional techniques, inadequate tracking and registration can lead to subclinical decentration and ablation nonuniformity, inducing coma. In a study by Mrochen et al., researchers looked at the clinical and theoretical effects of subclinical decentrations on the optical performance of the eye after PRK. They found that PRK-induced aberrations were significantly greater than preoperative aberrations, with subclinical decentration (<> Additionally, said Dr. Krueger, laser vision correction induces spherical aberration due to small optical zones, peripheral pulse reflectivity, nonoptimized aspheric profiles and biomechanical thickening in the periphery. The result? Diminished visual quality and contrast sensitivity.