Higher order aberrations in normal, dilated, intraocular lens, and laser in situ keratomileusis corneas

PURPOSE: To compare repeated measures of Zernike polynomial higher-order aberrations in 29 normal, 13 dilated normal, 11 intraocular lens (IOL), 11 laser in situ keratomileusis (LASIK), and one refractive keratectomy (RK)/IOL subject. METHODS: At least three Shack-Hartmann images were obtained from each subject, and higher order (uncorrectable by spectacles) Zernike representation was determined. For each subject, confidence intervals for each Zernike coefficient were determined as a function of pupil size. Significant (P<.05) coefficients were averaged within groups, and group means were compared to normal subjects. RESULTS: No differences were seen between the normal and dilated groups at P=.05. The patients with prior LASIK and IOL surgery showed statistically significant elevation of 4th order spherical aberration and total wavefront variance for pupil sizes greater than 5 mm, compared to normals. CONCLUSION: Both IOL and LASIK surgery elevate spherical aberration and wavefront variance, with increasing magnitude of effect with increasing pupil size, although pupillary dilation alone did not produce statistically different changes, as compared to normal subjects. These findings demonstrate that IOL implantation can produce more net aberrations than LASIK, and demonstrate a new opportunity to optimize surgical results.