In present study, postoperative data were taken at 1 month, 3 and 6 months after surgery. The aim of our study was to study the changes in spherical aberration after conventional laser in situ keratomileusis (LASIK). The study was a prospective, observational study. 56 myopic eyes of 29 patients undergoing LASIK were studied. All patients were clinically evaluated for the visual acuity (uncorrected and best corrected), retinoscopy, corneal topography, wave front analysis with Hartmann–Shack wavefront analyzer, anterior segment optical coherence tomography(OCT), ultrasonic pachymetry and dilated retinal evaluation. Statistical analysis was performed using SPSS 15.0. Paired–samples t test, Wilcoxon Signed Ranks Test were applied. A P value of less than 0.05 was considered statistically significant. Our results showed that conventional LASIK treatment significantly induced the spherical aberration (Z 4, 0) for 1 month. Conclusion: Conventional LASIK significantly increases the postoperative spherical aberrations at 1, 3, and 6 months.