Abstract
Purpose :
To observe the 1-year changes in axial length (AL) and aniso-AL in both unilateral and bilateral anisomyopic children underwent orthokeratology (OK) treatment.
Methods :
A retrospective study was conducted. Medical records, including demographic data, refraction, and AL, of patients aged 7 to 14 years old who searched for vision correction with OK lens in Zhongshan Ophthalmic Center from June 2013 to September 2016 were reviewed. Anisomyopic subjects with baseline interocular difference in spherical equivalent (aniso-SE) no less than 1.0D [134, 58 with unilateral myopic anisometropia (UMA) and 76 with bilateral myopic anisometropia (BMA)] were recognized and set as experimental groups. Another 222 age and refraction-matched (in the more myopic eyes) subjects with baseline aniso-SE less than 1.0D were set as control groups [96 (C1) and 126 (C2) were matched with UMA and BMA, respectively]. SE was measured by cycloplegic subjective refraction and AL was measured by IOLMaster. All subjects accepted OK treatment for at least 1 year. The interocular difference in AL growth of each groups and the difference of aniso-AL change between the 2 matched groups after 1 year of OK treatment were compared.
Results :
After 1 year of OK treatment, the AL in UMA group significantly increased by 0.07 ± 0.19mm (p <0.001) and 0.34 ± 0.21mm (p <0.001) for the myopic and emmetropic eyes, respectively. Accordingly, the ansio-AL reduced by -0.27 ± 0.29 mm (p <0.001). For BMA group, axial elongation was 0.05 ± 0.18 mm (p =0.029) and 0.16 ± 0.21mm (p <0.001) for the more myopic and the less myopic eyes, respectively. Aniso-AL reduced by -0.12 ± 0.16 mm (p <0.001). In the control groups, AL in both eyes showed symmetrical elongation (0.16 ± 0.19mm and 0.17 ± 0.21mm in C1, 0.11 ± 0.17 mm and 0.12± 0.16 mm in C2, for more myopic and less myopic eyes, respectively) without significant change in aniso-AL (-0.01mm, p=0.52 in C1; and -0.01mm, p =0.18 in C2). A significant correlation between the changes in aniso-AL and baseline ansio-SER was found for all bilateral myopes (BMA and 2 control groups combined, r = -0.42, p <0.001).
Conclusions :
OK lens seems to show an inhibitory effect on both unilateral and bilateral myopic anisometropia, through greater retardation on axial elongation of the more myopic eyes. This therapeutic effect will be more obvious in the subjects with greater baseline anisometropia.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.