配戴角膜塑形镜后镜片偏心的两种测量方法比较

目的：:对比分析配戴角膜塑形镜后2种镜片偏心的测量方法。方法：:回顾性临床研究。选取2016年8月至2018年10月在温州医科大学附属眼视光医院完成角膜塑形镜验配并持续戴镜24个月的近视儿童77例，将戴镜前和戴镜3个月后的角膜地形图对比构建切向差异图，分析戴镜前和戴镜3个月后Kappa角距离的变化情况，然后通过MATL...

Comparison of Two Kinds of Decentration Methods for Measuring Changes after Wearing Orthokeratology Lenses

Objective: To compare the difference between two kinds of decentration methods for measuring changes after wearing orthokeratology lenses. Methods: In a retrospective analysis, about 77 children who met the criteria and insisted on wearing orthokeratology lenses for 24 months were recruited from August 2016 to October 2018 in the Eye Hospital, Wenzhou Medical University. Corneal tangential topography was used to compare changes from before wearing orthokeratology lenses to after wearing them for3 months. The changes in angle kappa distance before wearing orthokeratology lenses and after wearing them for 3 months were compared. The degree of decentration on the tangential difference map was analyzed with MATLAB. There were two decentration measurement methods (method 1: The decentration distance from the corneal vertex to the center of the optical zone; method 2: The decentration distance from the pupil center to the center of the optical zone) and the difference between the measurement methods was compared. A paired t-test was used to analyze the corneal flat radial refractive power (Kf), the corneal steep radial refractive power (Ks), the angle kappa distance, and the decentration distance of decentration 1 and decentration 2 between baseline and after wearing orthokeratology for 3 months. An independent sample t-test was used to analyze the differences in the two measurement methods in different decentration directions (superior, temporal, inferior, nasal). Pearson correlation analysis was used to analyze the relationship between axial length and decentration distance. Results: There was a statistically significant difference in axial elongation between baseline and after wearing orthokeratology lenses for 2 years (25.25±0.81 mm vs. 25.63±0.76 mm; t=-10.014, P<0.001). The baseline flat radial refractive power (Kf: 42.80±1.23 D) and steep radial refractive power (Ks: 44.09±1.40 D) were significantly higher than the Kf (41.00±1.73 D) and Ks (42.85±1.93 D) measured after wearing orthokeratology lenses for 3 months (tKf=8.893, PKf<0.001; tKs=5.903, PKs<0.001). But there was no statistically significant difference in angle kappa distance between the baseline and after wearing orthokeratology lenses for 3 months (0.27±0.21 mm vs. 0.29±0.21 mm). The decentration distance in decentration 1 showed no statistically significant difference from the distance in decentration 2 (0.64±0.31 mm vs. 0.63±0.35 mm). The direction of the decentration was mainly turned to the temporal side in both methods. Both the decentration distance of decentration 1 (r=-0.332, P=0.003) and the distance of decentration 2 (r=-0.310, P=0.006) showed a negative correlation with axial length during orthokeratology lens wear for 2 years. Conclusions: After wearing orthokeratology lenses, the angle kappa does not show a significant change. The decentration distance measured from the corneal vertex to the optical center shows no statistically significant difference with the decentration distance from pupil center to optical center.