Optical quality and visual discrimination capacity after myopic LASIK with a standard and aspheric ablation profile

Abstract

Purpose: To determine whether the eye's optical quality is correlated to the visual discrimination capacity of patients treated with LASIK using two different ablation algorithms.

Methods: Visual discrimination was evaluated by the disturbance index under low illumination (Halo v1.0 software, Laboratory of Vision Sciences and Applications) in two groups of patients who underwent LASIK with two different ablation algorithms using the Allegretto Wave Eye-Q 400 Hz laser (WaveLight AG). In the first group (standard group; 30 eyes), corneal ablations were performed with the standard algorithm (preoperative spherical equivalent refraction -3.20±1.70 diopters [D]). In the second group (Q-optimized group; 38 eyes; spherical equivalent refraction -3.40±1.90 D), the ablations were made with the Q-optimized (F-CAT) algorithm. Optical quality of the eye was calculated by the Strehl ratio measured with a double-pass device (OQAS, Visiometrics SL).

Results: After LASIK, both the Strehl ratio as well as visual discrimination capacity diminished in both groups, although the changes were significantly greater in the standard group than in the Q-optimized group.

Conclusions: A high correlation was found between the Strehl ratio and the disturbance index in patients who underwent LASIK, regardless of the ablation algorithm applied. Optical and visual deterioration were greater after standard ablation.