WASCA像差分析仪与主觉验光测量散光的差异及影响因素分析

Accuracy of the WASCA aberrometer refraction compared to manifest refraction in astigmatism and its influencing factors

目的分析WASCA像差分析仪与主觉验光测量散光的差异及影响因素。方法分别用两种方法测量360例(组Ⅰ)近视散光患者,比较其散光度数和轴位的差异。从中选出46例(组Ⅱ),分析这些差异与第3～14项Zernike系数(C3～C14)的相关性。组Ⅰ、组Ⅱ各分2个亚组:负柱镜轴靠近90°和靠近180°组(分别称组Ⅰ90,组Ⅰ180和组Ⅱ90,组Ⅱ180)。结果组Ⅰ:WASCA与主觉验光散光度数差值(CA-CS)平均为(0.06±0.30)D(P<0.01);轴位差值绝对值(︱AA-AS︱)平均为(7.4±9.7)°;散光度数低于-0.75D组平均︱AA-AS︱更大(P<0.01)。组Ⅱ:散光度数和轴位差异与C3～C14的回归方程:组Ⅱ180:CA-CS=0.135+1.215×C13;组Ⅱ90:CA-CS=0.153-0.681×C13-0.386×C7+0.790×C10,︱AA-AS︱=1.986+13.043×︱C8︱。结论WASCA像差分析仪与主觉验光测得散光度数接近,但测量低度散光轴位差异较大。次级散光C13对负柱镜轴靠近180°和90°组的度数差异影响相反,后者水平彗差越大,轴位差值越大。

Abstract Objective The aim of present study was to investigate the accuracy of WASCA aberrometer refraction compared to manifest refraction in astigmatism and analyze the possible influencing factors. Methods WASCA and manifest refraction was performed on 360 individuals with myopia and the data of right eyes was collected （ group Ⅰ）. The cylindrical magnitude and axis differences between the two methods were compared. Forty-six subjects were randomly chosen from group I to study the correlation between those differences and C3 to C14 order Zernike coefficients （ group Ⅱ）. According to the axis 45° and 135° ,subjects in each group were divided into two subgroups： negative cylinder axis adjacent to 90°and 180° （group Ⅰ90 ,group Ⅰ180 ,group Ⅱ90 ,and group Ⅱ180）. Results In group I,the mean difference of cylinder magnitude between WASCA （CA ） and manifest refraction（ Cs ） was （0. 06 ± 0. 30） D （ P 〈 0. 01 ）. The mean absolute value of difference of cylinder axis between the two methods （ ｜ AA - AS ｜ ） was （7.4 ±9.7 ）° in subjects whose cylinder magnitudes were less than -0.75 D, the mean ｜ AA -AS ｜ was larger（ P 〈 0. 01 ）. In group Ⅱ,through multiple linear regression analysis combined with stepwise regression,the final multiple regression equations were as follows： groupⅡ180： CA -CS =0.135 ＋1.215 × C13;group Ⅱ90： CA -CS = 0.153 -0.681 ×C13 -0.386 × C7 ＋0.790 × C10, ｜ AA - AS ｜ = 1. 986 ＋ 13. 043 × ｜ C8 ｜. Conclusion WASCA aberrometer is accurate in predicting cylinder magnitude but less effective for the measurement of axis in low astigmatism eyes. WASCA plays opposite effects on cylinder magnitude difference of secondary astigmatism in comparison with manifest refraction in the subjects with negative cylinder axes adjacent to 180° and 90°. The effects of higher-order aberrations on magnitude differences are more comprehensive in the eye with the negative cylinder axes adjacent to 90°, and magnitude of horizontal coma may affect the difference of axis in both two methods.