Effect of Previous Myopic Laser In Situ Keratomileusis on Contrast Sensitivity After Diffractive Multifocal Intraocular Lens Implantations

Objective: To evaluate effects of previous myopic laser in-situ keratomileusis (LASIK) on decrease in contrast sensitivity after implantation of diffractive multifocal intraocular lens (MF-IOL). Methods: Retrospective case series included eyes that were implanted diffractive MF-IOLs after myopic LASIK. Contrast sensitivity was measured 1 month postoperatively and the area under log contrast sensitivity (AULCSF) was calculated. Principle component analysis (PCA) was used for extracting principal factors related with the previous LASIK and MF-IOL implantation. Effects of decrease in postoperative AULCSF and contrast sensitivity at each spatial frequency were evaluated using step-wise multiple regression analysis. Results: Twenty-six eyes of 20 patients were included. The mean postoperative uncorrected distance visual acuity was -0.06 ± 0.13 logMAR (20/17 in Snellen) and all eyes achieved 20/20 or better. The PCA determined central corneal thickness (CCT), distance-corrected near visual acuity, and absolute manifest refraction as principal factors. The multiple regression analysis revealed that the AULCSF showed significant decrease with a thinner CCT (P=0.017), while a particular trend was not found in the analysis results at the spatial frequencies. Conclusion: Degradation in contrast sensitivity after implantation of MF-IOLs in post-LASIK eyes was more affected by the amount of the previous LASIK corrections.