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 ( 0.05). Spherical-like, coma-like, and
secondary astigmatism HOA RMS increased significantly ( ≤ 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 ( ≤ −0.529, < 0.001). However, after 1 year of treatment, this correlation was only statistically significant for 12 cpd
spatial frequency ( ≤ −0.565, < 0.001). Spherical-like RMS for 6 mm pupil size correlated with irregularity of the LD ( = −0.420,
< 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.This research was supported in part by Projects PTDC/SAUBEB/098391/2008//FCOMP-01-0124-FEDER-010897,PTDC/SAU-BEB/098392/2008, and Strategic Funding UID/FIS/04650/2013
