角膜塑形术后光学治疗区大小及偏心对光学及视觉质量的影响

Influence of the Diameter and Decentration of the Treatment Zone on Optical Quality and Visual Performance after Orthokeratology

目的:分析角膜塑形镜配戴后角膜高阶像差、对比敏感度的变化,以及光学治疗区大小及偏心对二者的影响。方法:前瞻性临床研究。选取2017年3-8月于温州医科大学附属第三医院验配角膜塑形镜的近视儿童31例(31眼),测量戴镜前及戴镜1个月后的角膜地形图、对比敏感度、角膜高阶像差,分析光学治疗区大小及偏心情况对角膜高阶像差、对比敏感度变化的影响。对比敏感度以对比敏感度函数对数曲线下面积(AULCSF)衡量大小。采用配对t检验、Pearson相关分析、逐步多项线性回归分析等方法进行统计。结果:角膜塑形镜配戴1个月后,光学治疗区直径(3.48±0.49)mm,偏心距离(0.64±0.27)mm,偏心方向以颞下方为主(45%)。角膜总高阶像差、球差、垂直彗差、水平彗差均较配戴前明显增加(t=10.99、10.19、-2.21、-3.50,P<0.05);光学治疗区垂直偏心距离(标准化B=0.620,P=0.001)和水平偏心距离(标准化B=0.422,P=0.049)分别是影响角膜垂直彗差增加量和水平彗差增加量的唯一因素。配戴1个月后亮环境及暗环境AULCSF有下降趋势,但与戴镜前相比差异无统计学意义;亮环境AULCSF下降幅度与屈光度改变量有关(标准化B=0.452,P=0.021),而暗环境AULCSF下降幅度则与屈光度改变量(标准化B=0.528,P=0.004)、偏心距离(标准化B=0.458,P=0.027)均相关。结论:角膜塑形镜偏心会导致角膜高阶像差增加,但对对比敏感度影响不大。

Objective:To analyze the changes in corneal higher order aberrations(HOAs)and contrast sensitivity(CS)after orthokeratology(ortho-K)treatment,and their correlation with the magnitude of lens decentration.Methods:This was a prospective study.Thirty-one patients(31 eyes)who had undergone orthokeratology treatment from March to August 2017 in 3rd Affiliated Hospital of Wenzhou Medical University were chosen for the study.Corneal topography,CS and corneal HOAs were measured before and one month after ortho-K lens treatment,in addition,the diameter and decentration of the treatment zone and their inf luence on corneal HOAs and CS were analyzed.CS was expressed as area under log contrast sensitivity function(AULCSF)was a paired-t test,pearson correlation and stepwise multiple linear regression were used to analyze the data.Results:The mean TxZ diameter was 3.48±0.49 mm,while the mean decentration of TxZ was 0.64±0.27 mm,mostly toward the inferior temporal quadrant(45%).The root mean squares(RMS)of the total corneal HOAs,corneal spherical aberrations corneal vertical coma aberrations and corneal horizontal coma aberrations increased after one month of treatment(t=10.99,10.19,-2.21,-3.50,P<0.05).The vertical decentration of TxZ was significantly correlated with the corneal vertical coma aberrations(standard B=0.620,P=0.001),while the horizontal decentration was significantly correlated with the corneal horizontal coma aberrations(standard B=0.422,P=0.049).The photopic and mesopic AULCSF tended to decrease,but there were no significant differences.The change in photopic AULCSF only correlated with the change in diopters(standard B=0.452,P=0.021),while the change in mesopic AULCSF correlated with both the change in diopters(standard B=0.528,P=0.004)and the decentration of TxZ(standard B=0.458,P=0.027).Conclusions:Decentered othokeratology lenses increase corneal HOAs but do not affect CS.