配戴角膜塑形镜对成像质量的影响

Effect of orthokeratology on ocular imaging quality

目的探讨配戴角膜塑形镜前后角膜、眼内、全眼去除低阶像差的像质参数的变化趋势。设计前瞻性病例系列。研究对象选取沈阳爱尔眼视光医院2017年3-6月期间配戴角膜塑形镜者34例(均选右眼)为研究对象,年龄(11.68±1.70)岁,等效球镜(-3.43±1.42)D。方法应用iTrace视功能分析仪测量5 mm瞳孔直径下戴镜前,戴镜后1周,1、3、6个月的角膜、眼内、全眼的像质参数。像质参数包括在5、10、15、20、25、30周/度(c/d)六个空间频率下的去除低阶像差的调制传递函数值(MTF)和斯特列尔比值(SR)。戴镜前后各像质参数比较采用重复测量方差分析。主要指标MTF,SR。结果角膜、眼内、全眼的低中高频MTF值和SR值在戴镜后不同时间点均较戴镜前下降(P均<0.05)。在25 c/d空间频率下,戴镜后1个月角膜MTF值较戴镜后1周下降(P=0.042)。在5 c/d空间频率下,戴镜后1、3个月眼内MTF值较戴镜后1周下降(P=0.027、0.004)。在10、20、25 c/d空间频率下,戴镜后3个月眼内MTF值较戴镜后1周下降(P=0.029、0.013、0.020),戴镜后6个月MTF值较戴镜后3个月提高(P=0.020、0.019、0.042)。在15 c/d空间频率下,戴镜后6个月眼内MTF值较戴镜后3个月提高(P=0.037)。戴镜后1、3个月眼内SR值较戴镜后1周下降(P=0.039、0.015),戴镜后6个月较戴镜后3个月提高(P=0.032)。其余像质参数在戴镜后各时间点两两比较均无统计学差异(P均>0.05)。结论配戴角膜塑形镜6个月内,去除低阶像差的各像质参数在戴镜后均较戴镜前降低,表明戴镜后去除低阶像差后的眼成像质量下降。角膜高频MTF值,眼内低中高频MTF值和SR值在戴镜后组间存在变化,但戴镜后6个月时这些像质参数恢复到戴镜后1周时水平。

Objective To investigate the change trend of corneal,internal,ocular imaging quality parameters of subtracted lower order aberration before and after orthokeratology(OK).Design Prospective case series.Participants Thirty-four patients(34 right eyes),mean(11.68±1.70)years old,spherical equivalent diopter(-3.43±1.42)D,who had undergone OK treatment from March to June 2017 in Shenyang Aier Eye Hospital,were chosen for the study and followed up for 6 months.Methods Corneal,internal,ocular imaging quality parameters were measured with the iTrace visual function analyzer under a 5 mm pupil diameter at baseline and after 1 week,1 month,3 months,and 6 months of OK lens wearing.Imaging quality parameters include the subtracted lower order aberration modulation transfer function(MTF)at spatial frequencies of 5,10,15,20,25,30 cycle/degree(c/d)and strehl ratio(SR).Imaging quality parameters before and after OK were compared with repeated ANOVA.Main Outcome Measures MTF,SR.Results Corneal,internal,ocular low-middle-high spatial frequencies MTF and SR were significantly reduced at different time points after OK in comparison with baseline(all P<0.05).At a spatial frequency of 25 c/d,the corneal MTF decreased after 1 month of OK compared with 1 week after OK(P=0.042).At a spatial frequency of 5 c/d,the internal MTF decreased after 1,3 months of OK compared with 1 week after OK(P=0.027,0.004).At spatial frequencies of 10,20 and 25 c/d,the internal MTF decreased after 3 months of OK compared with 1 week after OK(P=0.029,0.013,0.020),and increased after 6 months of OK compared with 3 months after OK(P=0.020,0.019,0.042).At a spatial frequency of 15 c/d,the internal MTF increased after 6 months of OK compared with 3 months after OK(P=0.037).The internal SR decreased after 1,3 months of OK compared with 1 week after OK(P=0.039,0.015),and increased after 6 months of OK compared with 3 months after OK(P=0.032).There were no statistical differences among the other time points of post-OK(all P>0.05).Conclusion All the subtracted lower order aberration imaging quality parameters decreased after OK,indicating that the subtracted lower order aberration imaging quality declined.Corneal high spatial frequency MTF,internal low-middle-high spatial frequencies MTF and SR changed between the post-OK groups,but the change of 6 months returned to the level of 1 week after OK.