Abstract:

Objective To investigate the changes of axial length (AL), central corneal thickness (CCT), and corneal endothelial cell density(CECD) after wearing orthokeratology (ortho-k) lens in adolescent with myopic anisometropia. Design Retrospective case series. Participants 21 myopic anisometropic adolescent (42 eyes) from  2011 to 2013, aged between 8 and 15 years old, wearing the ortho-k lens more than 3 years in Beijing Tongren Eye Care Center. Methods The eyes were divided into high myopia and low myopia group according to the myopic degrees. The changes in AL, CCT, and CECD were measured before and 6 months, 1 year, 2 years and 3 years after wearing ortho-k lens. Data were analyzed using repeated measured ANOVA. Main Outcome Measures AL, CCT, CECD. Results The AL of high myopia group before and after ortho-k lens wearing for 6 months, 1 year, 2 years, 3 years was (25.16±0.78) mm, (25.27±0.81)mm, (25.43±0.91)mm, (25.50±0.85)mm and (25.64±0.87)mm respectively, and the data of low myopia group was (24.13±0.99)mm, (24.38±0.96)mm, (24.49±1.00)mm, (24.71±0.94)mm and (24.88±1.01)mm respectively. During the 3 years of observation period, the AL of both eyes increased every year after ortho-k lens wearing (F=48.2; P=0.000). The gap of AL between low myopic eyes and highly myopic eyes had significantly decreased (F=9.494; P=0.000) from (1.03±0.45)mm to (0.90±0.40)mm, (0.85± 0.39)mm, (0.79±0.41) mm and (0.76±0.44) mm. The CECD of highly myopic eyes before and after ortho-k lens wearing for 6 months, 1 year, 2 years, 3 years was (3362.57±278.73)/mm2, (3393.67±325.88)/mm2, (3333.76± 288.72)/mm2, (3276.90±240.49)/mm2 and (3259.71±357.41)/mm2, and the data of low myopic eyes was (3365.62±352.75)/mm2, (3387.62±363.57)/mm2, (3314.05±270.12)/mm2, (3290.71±327.64)/mm2 and (3307.05±357.12)/mm2 respectively. With the time prolonged, the CECD decreased (F=4.386; P=0.000), but there was no significant difference between the two groups. Before and after wearing ortho-k lens for 6 months, 1 years, 2 years and 3 years, the CCT data of highly myopic eyes was (548.81±28.34) μm, (531.43±33.30) μm, (526.05±30.84) μm, (523.38±27.54) μm and (525.29±27.92) μm respectively, and data of low myopic eyes was (549.76±28.72) μm, (536.90± 26.51) μm, (534.24±27.67) μm, (534.19±25.84) μm and (531.76±27.16) μm respectively. The baseline CCT of both eyes was not significantly different, both group reduced by the 6-month visit (F=56.843; P=0.000), and remained unchanged thereafter. Conclusions Orthokeratology treatment can reduce the axial length gap in adolescent with myopic anisometropia. The corneal shape remains stable within 6 months. (Ophthalmol CHN, 2017, 26: 131-134)

Key words: orthokeratology, myopic anisometropia, axial length, central corneal thickness, corneal endothelial cell density