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.
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.
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.
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.
Department of Optometry and Vision Sciences (L.E.D.), University of Melbourne, Victoria, Australia; and Eye Technology (R.L.), Carlton, Victoria, Australia.
Address correspondence and reprint requests to Laura E. Downie, B.Optom., Ph.D., F.A.C.O., P.G.Cert.Oc.Ther., Dip.Mus.(Prac), A.Mus.A., Cornea and Contact Lenses, Department of Optometry and Vision Sciences, University of Melbourne, Parkville Victoria 3010, Australia; e-mail: email@example.com
R. Lowe first reported on the temporal refractive stability and thus the apparent regulation of progressive myopia, among a cohort of 10 pediatric patients who received OK treatment in his private rooms for up to 4 years at an invited lecture delivered to the Annual General Meeting of the Contact Lens Society of Australia, October 2001. R. Lowe has on occasion acted as a paid consultant for Paragon Vision Sciences.
L. E. Downie presented this paper at the 13th International Cornea and Contact Lens Conference, Sydney, Australia, October 9–11, 2010.
The authors have no funding or conflicts of interest to disclose.
Accepted April 25, 2013