配戴角膜塑形镜对成像质量的影响

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。（眼科， 2020, 29： 128-132）

Effect of orthokeratology on ocular imaging quality

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.