Assessment of aberrations and visual quality differences between myopic and astigmatic eyes before and after contact lens application.

Objective: To evaluate the aberration and visual quality differences between myopic and astigmatic eyes before and after contact lens application by using corneal aberrometer and low- contrast sensitivity chart.

Methods: Eighty eyes of 40 patients were included in this study. Patients were divided into two groups as myopic (40 eyes, n=20) and astigmatic groups (40 eyes, n=20). We used aspheric Balafilcon A (Purevision and Purevision Toric Bausch&Lomb, Rochester, USA) lenses for each group. Corneal aberrations and low-contrast sensitivity values were measured and compared for each patient in both groups.

Results: There were no statistically significant differences between myopic and astigmatic groups when we compared low-contrast sensitivity values for both on- and off-eyes. Mean total higher-order aberration (HOA) values for off-eye, were 0.29±0.10 μm, and 0.33±0.10 μm for on-eye in the myopic group, while they were 0.42±0.14 μm in off-eye and 0.37±0.23 μm in on-eye in the astigmatic group. Off-eye mean coma, irregular astigmatism and total higher-order aberration RMS (root-mean-square) values were significantly higher in the astigmatic group compared to the myopic group (p=0.006, p=0.001, p=0.001) but mean on-eye RMS values were not.

Conclusion: Myopic and astigmatic patients differ in terms of high-order aberrations and these differences cannot be equalized after contact lens application, but visual quality can be improved in both patients by using contact lenses.