Anderson Heather A, Ravikumar Ayeswary, Benoit Julia S, Marsack Jason D
University of Houston College of Optometry, Houston, TX, USA.
Texas Institute for Measurement, Evaluation, and Statistics, Houston, TX, USA.
Transl Vis Sci Technol. 2019 Dec 12;8(6):32. doi: 10.1167/tvst.8.6.32. eCollection 2019 Nov.
Objective refraction based on wavefront aberration measures is a potential tool for patients unable to participate in a subjective refraction, but the selection of a single pupil diameter for determination of the objective refraction may pose challenges. The purpose of this study was to investigate the impact of pupil diameter on determination of objective refractions for adults with and without Down syndrome (DS) and predicted change in acuity with increasing pupil diameter.
Wavefront error was obtained from 27 adults with DS and 24 controls, and metric-optimized refractions were identified for 4- and 6-mm pupil diameters. Total dioptric difference between refractions for the two pupil sizes was calculated, and repeated measures analysis of variance was used to evaluate differences in refractions. Next, five control observers read acuity charts produced to simulate image quality of each subject if the same refraction was applied for both a 4- and 6-mm pupil diameter. A comparison of acuity with performance on a clear chart was used to calculate letters lost for each chart. Repeated measures analysis of variance was used to test for differences in letters lost from 4- and 6-mm diameters.
The dioptric difference between refractions for 4- and 6-mm pupils was significantly greater in subjects with DS (0.51 diopters vs. 0.19 diopters, = 0.0012). Letters lost for predicted acuity was less for the 4-mm diameter than 6 mm for charts representing DS eyes (6.5 letters vs. 11 letters, < 0.0001), as well as for typical eyes (4.5 letters vs. 8 letters, < 0.0001).
Differences between refractions by pupil diameter were similar to the repeatability of subjective refraction. Visual acuity differences were clinically small, suggesting similar performance for objective refractions with increasing pupil diameter.
This work quantifies the potential impact of pupil diameter change on the performance of wavefront optimized refractions in clinical patients.
基于波前像差测量的客观验光对于无法参与主观验光的患者而言是一种潜在工具，但选择单一瞳孔直径来确定客观验光可能会带来挑战。本研究的目的是调查瞳孔直径对患有和未患有唐氏综合征（DS）的成年人客观验光测定的影响，以及随着瞳孔直径增加预测视力的变化。
从27名患有DS的成年人和24名对照者中获取波前误差，并确定4毫米和6毫米瞳孔直径的度量优化验光结果。计算两种瞳孔大小的验光结果之间的总屈光度差异，并使用重复测量方差分析来评估验光结果的差异。接下来，五名对照观察者阅读制作的视力表，以模拟如果对4毫米和6毫米瞳孔直径应用相同验光结果时每个受试者的图像质量。将视力与清晰视力表上的表现进行比较，以计算每个视力表丢失的字母数。使用重复测量方差分析来测试4毫米和6毫米直径丢失字母数的差异。
患有DS的受试者中，4毫米和6毫米瞳孔的验光结果之间的屈光度差异明显更大（0.51屈光度对0.19屈光度，P = 0.0012）。对于代表DS眼睛的视力表，预测视力丢失的字母数在4毫米直径时比6毫米时少（6.5个字母对11个字母，P < 0.0001），对于典型眼睛也是如此（4.5个字母对8个字母，P < 0.0001）。
瞳孔直径引起的验光结果差异与主观验光的可重复性相似。视力差异在临床上较小，表明随着瞳孔直径增加，客观验光的表现相似。
这项工作量化了瞳孔直径变化对临床患者波前优化验光性能的潜在影响。
