Higher-Order Aberrations Following Ray Trace LASIK and the Impact of Eye Movement on Coma

To assess ocular higher-order aberrations (HOAs) following ray trace guided laser in situ keratomileusis (LASIK).

Retrospective review at a single-site ophthalmology practice. Two hundred and fifty eyes of 250 patients with myopia and astigmatism undergoing ray trace LASIK were randomly reviewed (Wavelight Plus, Alcon). The InnovEyes Sightmap (Alcon) diagnostic device was used for whole-eye wavefront aberrometry, tomography, and biometry assessment preoperatively and 3 months post-operatively. Ocular HOA, ablation decentration, intraoperative pupil size, and pupil tracking were assessed. Intraoperative eye tracking of x and y coordinates were separately averaged to calculate mean and standard deviation of movement along the x-axis and y-axis to assess eye movement.

Total HOA RMS (n = 250 eyes) increased marginally from 0.306 ±0.102 to 0.371 ±0.135 (p < 0.001) post-operatively. Spherical aberration decreased (0.092 ±0.112 to 0.056 ±0.125, p < 0.001). There was no significant difference in preoperative to postoperative vertical coma under -3D SEQ and horizontal coma under 2D SEQ. In eyes with 4D or more myopia treatment, post-operative vertical and horizontal coma was moderately correlated with the product of ablation depth and vertical and horizontal decentration (R² 0.51, p < 0.001, R²=0.34, p < 0.001, respectively). Multivariate analysis further showed this was correlated to eye movement.

Ray trace LASIK results in a minimal increase in total ocular HOA which is statistically but not clinically significant. Spherical aberration decreases. In larger treatments, there is an increase in coma which correlates with vertical and horizontal decentration of ablation, likely due to eye movement during surgery.