| ObjectiveTo observe the changes of ocular biological parameters and related factors of children with low and moderate myopia after wearing the orthokeratology.Methods86 children with an average age of 11.0±1.9 years(from 8～14y),including40 males and 46 females,were recruited at the Aier Eye Hospital from January to December 2018.Spherical equivalent(SE)was(-3.83±1.19)D(from-0.50 D ～-6.00D).During wearing orthokeratology 12 months(OD was selected),we conducted a self-controlled perspective study.According to the spherical equivalent,they were divided into two groups,namely the low myopia group(-0.50～-3.00)D and the moderate myopia group(-3.00～-6.00)D.Axial length(AL),central corneal thickness(CCT),anterior chamber depth(ACD),and lens thickness(LT)as ocular constructive parameters were measured.Meanwhile,anterior surface curvature(including flat K steep K),astigmatism and white to white(WTW)as corneal morphology parameters were measured.All data were remeasured at baseline,6 months and 12 months by Lenstar LS900.We observed the changes of biological parameters before and after wearing orthokeratology,analyzed the relationship between biological parameters,summarized and compared the variation of biological parameters at different time points in patients with low and moderate myopia.Statistical analyses were performed using the SPSS 23.0 software.Results1.AL increased with time.The AL of the eyes in the low-diopter myopia group before and at 6 months and 12 months after wearing orthokeratology was(24.27±0.76)mm,(24.49±0.80)mm,(24.60±0.80)mm,and in the moderate-diopter group was(25.29±0.82)mm 、(25.44±0.84)mm 、(25.51±0.87)mm respectively.The difference of AL at different times was statistically significant in two groups.(F=77.83,P=0.000;F=42.22,P=0.000).Meanwhile,compared with low-diopter group(0.33±0.17)mm,the AL growth in moderate-diopter group(0.23±0.19)mm was greater in 12 months after wearing.The difference was statistically significant(t=2.61,P=0.011).2.CCT gradually became thinner with time.The CCT of the eyes in the low-diopter myopia group before and at 6 months and 12 months after wearing orthokeratology was(538.55±31.07)μm,(533.20±34.68)μm,(530.94±33.79)μm,and in the moderate-diopter group was(536.97±30.07)μm,(532.35±29.02)μm and(530.62±29.78)μm.The difference of CCT at different time points was statistically significant(F=18.99,P=0.000;F=25.72,P=0.000).3.ACD shallowed over time.The ACD of the eyes in the low-diopter myopia group before and at 6 months and 12 months after wearing orthokeratology was(3.21±0.22)mm,(3.20±0.23)mm,(3.18±0.23)mm and in the moderate-diopter group was(3.18±0.24)mm,(3.17±0.28)mm,(3.16±0.27)mm.The difference of ACD at different time points was statistically significant in two groups.(F=2.79,P=0.067;F=5.04,P=0.013)4.LT thickened over time.The LT of the eyes in the low-diopter myopia group before and at 6 months and 12 months after wearing orthokeratology was(3.39±0.15)mm,(3.41±0.14)mm,(3.43±0.15)mm and in the moderate-diopter group was(3.38±0.20)mm,(3.40±0.20)mm,(3.41±0.18)mm,The difference of ACD at different time points was statistically significant in two groups.(F=14.56,P=0.000;F=13.02,P=0.000).5.Flat K became flatter over time.The flat K of the eyes in the low-diopter myopia group before and at 6 months and 12 months after wearing orthokeratology was(42.45±1.23)D,(40.50±1.49)D,(40.54±1.53)D,and in the moderate-diopter group was(42.63±1.05)D,(39.49±1.21)D,(39.31±1.34)D,respectively.The difference of flat K at different times was statistically significant in two groups.(F=264.14,P=0.000;F=255.95,P=0.000).6.Step K became flatter over time too.The step K of the eyes in the low-diopter myopia group before and at 6 months and 12 months after wearing orthokeratology was(43.64±1.38)D,(41.57±1.46)D,(41.67±1.46)D,and in the moderate-diopter group was(44.05±1.08)D,(40.94±1.15)D,(40.90±1.29)D,respectively.The difference of flat K at different times was statistically significant in two groups.(F=273.24,P=0.000;F=196.48,P=0.000).7.AST was not statistically significant at different times in both groups.(F=1.04,P=0.357;F=0.95,P=0.390)8.WTW was not statistically significant at different times in both groups.(F=1.75,P=0.180;F=1.16,P=0.318)9.By analyzing the influencing factors of the changes in ocular biological parameters of the eyeball,we found that the changes in AL were correlated with the baseline age,SE,FK,SK and WTW(r=-0.351、0.315、-0.413、-0.404 and0.254,P<0.05);FK was correlated with SE and AL(r=0.341、-0.550,P<0.05);Changes in SK were correlated with SE and AL(r=0.353、-0.424,P<0.05).ConclusionsThe AL changes of children with moderate myopia after wearing orthokeratology were less than those with low myopia.Long-term corneal flattening,shallow anterior chamber depth,increased crystal thickness,and other changes will occur,but there is no significant change in corneal diameter and astigmatism.The tendency of the anterior chamber depth to become shallow and the lens to become thicker may reduce the peripheral hyperopiadefocusing,which is related to the mechanism of orthokeratology correction and delaying the progression of myopia. |
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