Abstract
Purpose :
To perform a prospective, observational clinical study to determine the combined suppressive effects of orthokeratology (OK) and 0.01% atropine instillation on axial length elongation in childhood myopia. We report the results of a 1-year follow-up of this study.
Methods :
Children aged 8 to 12 years with spherical equivalent refractions of -1.00 to -6.00 diopters (D) and astigmatism of -1.50 D or less were included and randomly assigned to treatment with OK with 0.01% atropine or OK alone. Both groups wore the OK contact lenses (Breath-O correct; Universal View Co., Ltd., Tokyo, Japan) while sleeping. The OK with 0.01% atropine group started instillation of 0.01% atropine once nightly from 3 months after the start of OK. The axial length was measured every 3 months using noncontact optical biometry (IOLMaster; Carl Zeiss Meditec, Dublin, CA), and the 3-month axial length served as the baseline value. Increases in axial length over 1 year were compared between the two groups and analyzed in relation to age and spherical equivalent refraction at study entry in both groups. The measured refractive and axial length values were averaged from both eyes of the subjects.
Results :
Forty subjects (20 subjects in the OK with 0.01% atropine group and 20 subjects in the OK alone group) completed the 1-year follow-up examination. At study entry, age, sex, spherical equivalent refraction, and axial length did not differ significantly between the groups. Increases in axial length over 1 year were 0.09 ± 0.12 and 0.19 ± 0.15 mm for the OK with 0.01% atropine group and the OK alone group, respectively, a difference that reached significance (P = 0.0356, unpaired t-test). No significant correlations were found in either group between ages and increases in axial length. A significant correlation was found between the spherical equivalent refraction and increased axial length in the OK alone group (Pearson’s correlation coefficient; r = 0.805, P < 0.001) but not in the OK with 0.01% atropine group (r = 0.306, P = 0.189; Figure).
Conclusions :
Combined treatment of OK and 0.01% atropine instillation suppressed axial length elongation more than OK alone in childhood myopia. Although OK was less effective in slowing axial elongation in subjects with lower degrees of myopia, this weakness was covered by the addition of 0.01% atropine instillation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.