Higher order wavefront aberrations of cornea and magnitude of refractive correction in laser in situ keratomileusis

Abstract

Objective To assess the relation between magnitude of refractive correction and changes in higher order wavefront aberrations of the cornea after laser in situ keratomileusis. Design Prospective, consecutive, nonrandomized comparative trial (self-controlled). Participants One hundred eyes of 53 patients with myopia (−2.0 to −13.0 diopters) were included. Intervention Laser in situ keratomileusis was performed. Videokeratography measurements were conducted before and 1 month after surgery. Main outcome measures The videokeratography data were used to calculate the higher order wavefront aberrations of the cornea for both small (3 mm) and large (6 mm) pupils. Results For a 3-mm pupil, the surgery significantly increased comalike (2.4 ± 1.3-fold, P < 0.001, paired t test) and spherical-like (1.8 ± 0.9-fold, P < 0.001) aberrations. For a 6-mm pupil, both comalike (4.4 ± 3.3-fold, P < 0.001) and spherical-like (9.4 ± 5.2-fold, P < 0.001) aberrations were significantly increased by surgery. The amount of achieved correction showed significant correlations with the changes in comalike (Pearson correlation coefficient r = 0.446, P < 0.001) and spherical-like ( r = 0.348, P < 0.001) aberrations for a 3-mm pupil, and comalike ( r = 0.566, P < 0.001) and spherical-like ( r = 0.693, P < 0.001) aberrations for a 6-mm pupil. The eyes that lost 2 or more lines of baseline spectacle-corrected visual acuity showed significantly larger induced increases in comalike ( P = 0.003, Mann-Whitney U test) and spherical-like ( P = 0.009) aberrations for a 3-mm pupil than those that either improved or remained within 1 line of spectacle-corrected visual acuity Conclusions Laser in situ keratomileusis, performed using the current algorithms, increases higher order wavefront aberrations of the cornea, dependent on the amount of refractive correction.