Corneal Reshaping Influences Myopic Prescription Stability (CRIMPS): An Analysis of the Effect of Orthokeratology on Childhood Myopic Refractive Stability

Objective: To determine whether overnight orthokeratology (OK) influences the progression rate of the manifest refractive prescription in myopic children, when compared with an age-and refraction-matched spectacle-wearing control group, over a period up to 8 years. Methods: The right eyes of control (n=30) and OK (n=26) children were compared. Treatment groups were matched for baseline age and refractive error. At baseline, children were younger than 16 years and showed manifest spherical refractive error more than 20.50 diopters. The minimum period of evaluation for each child was 2 years. Changes to manifest refractive prescription were compared between the groups in 2 yearly intervals up to 8 years. Results: On the whole, OK eyes showed a significantly (P<0.05) more stable myopic refractive prescription than control eyes over all of the 2-year treatment intervals. A subpopulation (n=18; 64%) of OK eyes demonstrated an apparent total arrest of manifest myopic refractive change. Symmetry in the vertical meridian of baseline corneal topography was associated with a greater degree of refractive stability in OK eyes. Conclusions: This retrospective study provides evidence that OK can reduce the rate of progression of childhood myopia over the long term. In addition, these findings offer some early insight into a potential indicator that may help predict the extent of refractive stability in individual eyes undergoing OK.