Abstract
Purpose: :
To study the influence of various ocular and demographic variables on the effect of reducing childhood myopia progression using myopic retinal defocus with a simultaneous clear retinal image.
Methods: :
Univariate and multivariate regression analysis were carried out to the 10 month results from the Dual-focus Inhibition of Myopia Evaluation in New Zealand clinical trial, a randomized, investigator blinded, cross-over study. 40 children (11-14) with progressing myopia wore the dual focus soft contact lenses (DF SCL) on one eye and single vision contact lenses (SV SCL) on the other eye for 10 months. The treatment effect is defined as the difference in myopia progression between the treatment eye (DF SCL) and the contra-lateral control eye (SV SCL) using cycloplegic auto-refractions. The impact of various independent variables (pupil diameters, accommodation and binocular performance, age, gender and ethnicity) to the treatment effect was analysed.
Results: :
In general, the eyes with DF SCL progressed less than the eyes with SV SCL. The progression rate of the contra-lateral control eye, photopic pupil diameter and the proportion of the treatment area from the myopic defocus treatment zone overlaying the near pupil were correlated to the treatment effect (r² = 0.28, p<0.01, r² = 0.20, p<0.01 and r² = 0.26, p<0.10 respectively). Combining myopia progression of the control eye and the treatment area over the pupil resulted in a correlation with the treatment effect of 62%.
Conclusions: :
The DF soft contact lens design which provides myopic retinal defocus and a simultaneous clear retinal image slows myopia progression. The relationship of pupil size and treatment area and children’s myopia progression rate are related to the treatment effect from the DF design.
Clinical Trial: :
www.anzctr.org.au 12605000633684
Keywords: myopia • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • refractive error development