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 -0.50 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.