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 coma-like (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 coma-like (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 coma-like (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 coma-like (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 coma-like (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.