Combination of orthokeratology lens with 0.01% atropine in slowing axial elongation in children with myopia: a randomized double-blinded clinical trial

BACKGROUND: To evaluate the additive effects of orthokeratology (OK) lenses and 0.01% atropine on slowing axial elongation in myopic children. METHODS: A prospective, randomized, double-blinded, placebo-controlled trial was conducted over a 12-month period. Sixty children aged 8 to 12 years with spherical equivalent refraction from − 1.00 to -4.00 D who had been wearing OK lenses successfully for 2 months (as baseline) were randomly assigned in a 1:1 ratio to combination group (combination of OK lens and 0.01% atropine eye drops) and control group (combination of OK lens and placebo). The primary outcome was change in axial length, along with secondary outcomes including change in pupil diameter (PD) and accommodative amplitude (AMP) at 12 months (measured at 4-month intervals). RESULTS: After 12 months, the overall axial elongation was 0.10 ± 0.14 mm and 0.20 ± 0.15 mm (p = 0.01) in the combination and control groups, respectively. The change in axial length in the two groups showed significant differences only in the first four months (median [Q1, Q3] (95% CI), -0.01 mm [-0.07, 0.05] (-0.06, 0.04) vs. 0.04 mm [0.00, 0.10] (0.02, 0.09); p = 0.04), but no difference thereafter. Multivariate linear regression analysis showed that the axial elongation was significantly slower in the combination group than in the control group (standard β = -0.10, p = 0.02). PD significantly increased by 0.45 mm [0.20, 0.68] at the 4th month visit (p < 0.001) and then remained stable in the combination group. The PD in the control group and AMP in the two groups remained stable from baseline to 12 months (all p > 0.05). CONCLUSION: The combination therapy was more effective than the OK lens alone in slowing axial elongation after 12 months of treatment, and mainly in the first 4 months. TRIAL REGISTRATION: The First Affiliated Hospital of Zhengzhou University, ChiCTR2000033904. Registered 16/06/2020, http://www.chictr.org.cn/login.aspx?referurl=%2flistbycreater.aspx