To evaluate the clinical effects of orthokeratology lens on children with myopic anisometropia.

Retrospective case series study. The data of 226 myopic anisometropia children, (10.83±1.56)years old, including 95 males and 131 females, fitted with orthokeratology(OK) lens in Beijing Tongren Hospital from June 2017 to June 2019 were collected. According to the lens wearing condition and baseline anisometropia, they were divided into four groups: group A1 with an average age of (10.68±1.66) years (bilateral OK lens wearing with low anisometropia, 1.0 D≤SE difference<2.5 D, 50 males and 61 females), group A2 with an average age of (11.24±1.38) years (bilateral OK lens wearing with moderate and high anisometropia, SE difference≥2.5 D, 10 males and 23 females), group B1 with an average age of (10.79±1.51) years (unilateral OK lens wearing with low anisometropia, 1.0 D≤SE difference<2.5 D, 17 males and 21 females) and group B2 with an average age of (10.97±1.60) years (unilateral OK lens wearing with moderate and high anisometropia, SE difference≥2.5 D, 18 males and 26 females). After wearing OK lens for one year, the changes of axial length(AL) and AL difference were observed and statistically analyzed.

(1) AL changes: after wearing OK-lens for one year, AL of each eye increased. In group A1, the AL of the more myopic eyes and the less myopic eyes increased by (0.20±0.21) mm and (0.24±0.22) mm respectively, and the difference was statistically significant (t=-3.208, P=0.002); in group A2, the AL growth of the more myopic eyes and the less myopic eyes were (0.04±0.11) mm and (0.17±0.14) mm, and the difference was statistically significant (t=-5.545, P<0.001). In group B1, the AL elongation of the more myopic eyes and the less myopic eyes were (0.14±0.21) mm and (0.39±0.23) mm, and in group B2, the AL growth of the more myopic eyes and the less myopic eyes were (0.11±0.14) mm and (0.54±0.24) mm, with statistically significant differences(t=-6.533, -11.643; all P<0.001). There was a linear correlation between AL elongation and age of the more myopic eyes and the less myopic eyes in group A1(correctedR²=0.208, 0.237) and group A2 (corrected R²=0.169, 0.360). There was no linear correlation of the more myopic eyes and the less myopic eyes between AL change and age or baseline myopia in group B1 (F=0.514, 1.205;P=0.602, 0.312) and group B2 (F=0.841, 0.056; P=0.439, 0.946). (2)Change of AL difference: after wearing OK lens for one year, the changes of AL difference in groupA1, A2, B1 and B2 were (-0.04±0.14) mm,(-0.13±0.13) mm,(-0.26±0.24) mm and (-0.43±0.25) mm, and the decrease of AL difference in moderate and high anisometropia groups were greater than that in low anisometropia groups (t =-3.211, -3.180; P=0.002, 0.002).There was a linear correlation between the reduction of AL difference and baseline anisometropia in group A1, A2 and B2 (corrected R²=0.099, 0.149, 0.230), and there was no linear relationship between the decrease of AL difference and the baseline anisometropia in group B1 (F=0.014, P=0.908).

Orthokeratology could effectively control the progression of myopia and to treat anisometropia. The effect of myopia control was better in the older binocular OK lens wearers, and for the patients with greater baseline anisometropia, the treatment effect of anisometropia was better.

Myopia; Anisometropia; Axial length; Orthokeratology