Analysis of corneal morphology after one-month discontinuation of orthokeratology treatment

Objective To observe whether the corneal morphology return to the baseline level after one-month treatment of orthokeratology. Methods Clinical data about patients (right eyes) who received orthokeratology treatment in our center from February 2015 to October 2017 were collected and analyzed, including the Q-value (8 mm), Rm (mean radius of curvature), Rper (mean radius of curvature in the 7 mm to 9 mm area), astigmatism, CCT (central corneal thickness), etc. Thibos vector analysis was performed for astigmatism calculation. Data at baseline (before wearing) and endpoint (after one-month of wearing) were compared, and the relationship between the brand of orthokeratology and corneal morphology were analyzed. Results Fifty-two patients (52 eyes) were involved in this study, with 17 males and 35 females, and their median age was 11 years (8-17 years). Annual spherical equivalent (SE) change was (-0.19±0.37) D and annual axial length (AL) change was 0.14 (0.09, 0.23) mm. Compared to baseline data, endpoint anterior and posterior Q-values increased with mean differences of 0.039 and 0.055 (P<0.05). Anterior corneal Rm values also increased with median difference of 0.060 mm, while the posterior corneal Rm values decreased with mean difference of -0.024 mm (P<0.05, respectively). Anterior corneal Rper values showed no significant change, while posterior corneal Rper values increased with mean difference of 0.039 mm (P=0.000). There was no difference regarding anterior or posterior astigmatism vector J0 and J45 (baseline vs endpoint). Decreased CCT values were observed with median difference of -6.5μm. There was no significant difference between the three orthokeratology brands in terms of baseline-endpoint comparisons of anterior Q-value, posterior Q-value, anterior Rm, posterior Rm, posterior Rper, and CCT. Conclusion Corneal morphology after one-month treatment of orthokeratology does not return to the baseline level, but the difference is very small. Orthokeratology may induce entire cornea to move backward, with posterior cornea surface protruding forward. Different brands of orthokeratology do not affect the restoring of corneal morphology.