| Aims: 1 、 Pattern-related visual stress(PRVS)refers to the perceptual difficulties experienced by some individuals when exposed to high contrast striped patterns.The present study was to investigate the effect of practice on global motion threshold in adults with and without PRVS and evaluate the consistency between the Wilkins & Evans Pattern Glare Test and global motion test.2、To investigate the effect of different spatial frequency and signal-noise ratio on the sensitivity of global motion in subjects with and without PRVS.3、To test if the sensitivity and perceived depth in global motion is directional independent,and evaluate the direction bias.Methods: 1、A total of 101 subjects were recruited and the Wilkins & Evans Pattern Glare Test was used to determine if a subject had PRVS.The threshold to detect global motion was measured with a random dot kinematogram.Each subject was measured 5 times at the first visit and again a month later.Receiver operating characteristic(ROC)curve analysis was applied to show the agreement between the two tests.2、A total of 91 subjects were recruited and the Wilkins & Evans Pattern Glare Test was used to determine if a subject had PRVS.The threshold to detect global motion was measured with 2 kinds of dots and 3 kinds of Gabor patterns,respectively.The threshold was compared between and within the 2 groups of sujects with and without PRVS.3、Ten subjects were recruited and tested the sensitivity and perceived depth of global motion in different directions.Rayleigh test was applied to determine if the distribution of test results was uniform on all directions,and directional bias was used to quantify the preference of certain direction.Results: 1、Twenty-nine subjects were classified as having PRVS symptoms and 72 were classified as normal subjects.At baseline,the threshold of sensitivity to detect global motion was significantly higher in subjects with PRVS(0.832 ± 0.098 vs.0.618 ± 0.228,p < 0.001).After 5 sessions,the difference between the normal and subjects with PRVS increased(0.767 ± 0.170 vs.0.291 ± 0.149,p < 0.001).In ROC analysis,the area under the curve(AUC)improved from 0.792 at baseline to 0.964 at the fifth session.After a one-month break,the difference between normal and subjects with PRVS was still significant(0.843 ± 0.169 vs.0.407 ± 0.216,p < 0.001)and the AUC was 0.875.2、Twenty-seven subjects were classified as having PRVS symptoms and 74 were classified as normal subjects.The threshold to detect global motion was significantly lower using Gabor patterns than dots(subjects with PRVS: 0.387 ± 0.228,0.217 ± 0.176,0.446 ± 0.239 vs.0.843 ± 0.169,0.869 ± 0.148,P < 0.001;Normal: 0.14 ± 0.104,0.096 ± 0.091,0.262 ± 0.181 vs.0.406 ± 0.216,0.458 ± 0.249,P < 0.001).The threshold of global motion in sujects with PRVS was always higher than nomal using Gabor patterns and dots(P < 0.001).3、In 9 subjects,the threshold to detect global motion was independent of directions(CV > 0.05,Rayleigh test).While for depth perception,all 10 subjects showed non-uniform distribution on the tested directions(CV < 0.05,Rayleigh test).To perceived depth,the directional bias was significantly greater than that in detection threshold test(0.34 ± 0.16 vs.0.10 ± 0.08,p < 0.05).Conclusion: 1、The ability to detect global motion is impaired in persons with PRVS and the difference increased after additional sessions of practice.2、The threshold to detect global motion was significantly lower using Gabor patterns than dots,and the results in sujects with PRVS was lower than nomal.3、There is an anisotropy in perceived depth in global motion and this anisotropy is not related to the uniform thresholds in detecting global motion. |
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