Corneal aberrations, contrast sensitivity, and light distortion in orthokeratology patients: 1-year results

Abstract

Purpose. To evaluate the corneal higher-order aberrations (HOA), contrast sensitivity function (CSF), and light distortion (LD) in patients undergoing orthokeratology (OK). Methods. Twenty healthy subjects (mean age: 21.40 ± 8 years) with mean spherical equivalent refractive error M = −2.19 ± 0.97 D were evaluated at 1 day, 1 month, and 1 year after starting OK treatment. Monocular LD, photopic monocular CSF, and corneal HOA for 6 mm pupil size were measured. Results. LD showed an increase after the first night (𝑝 < 0.05) and recovery to baseline after 1 month, remaining stable after 1 year (𝑝 > 0.05). Spherical-like, coma-like, and secondary astigmatism HOA RMS increased significantly (𝑝 ≤ 0.022) from baseline to 1-month visit, remaining unchanged over the follow-up. Contrast sensitivity for medium frequencies (3.0, 4.24, and 6.00 cpd) was significantly correlated with LD parameters at baseline (𝑟 ≤ −0.529, 𝑝 < 0.001). However, after 1 year of treatment, this correlation was only statistically significant for 12 cpd spatial frequency (𝑟 ≤ −0.565, 𝑝 < 0.001). Spherical-like RMS for 6 mm pupil size correlated with irregularity of the LD (𝑟 = −0.420, 𝑝 < 0.05) at the 1-year visit. Conclusion. LD experienced by OK patients recovers after one month of treatment and remains stable in the long term while optical aberrations remain significantly higher than baseline.