Abstract
Purpose :
Pattern glare refers to the symptoms of visual discomfort and perceptual distortions experienced by people while looking at repetitive striped patterns. The underlying neural mechanism is still unclear. Recent studies have suggested a strong correlation between pattern glare and migraine, which is known for deficit in global motion processing. The aim of this study was to study whether people with an abnormal degree of pattern glare, but no migraine, also have reduced ability to detect global motion.
Methods :
The degree of pattern glare was determined with the Wilkins & Evans Pattern Glare Test. Subjects looked at square waves patterns with spatial frequencies of 0.5, 3, or 12 cycles per degree (cpd) for 5 seconds and reported distortions perceived. The number of distortions at each spatial frequency was summed to give a score. A subject with a score of > 3 on the 3 cpd pattern or a score of > 1 on the 3-12 cpd difference was considered as abnormal. The threshold of detecting the global motion was measured in 15 abnormal and 15 normal subjects with random dot kinematogram. In each trial, the subjects’ task was to indicate whether the direction of the perceived global motion was vertically up or down. The proportion of the dots moving at the same direction was adjusted according to a 3-down-1-up staircase procedure from trial to trial. Threshold was estimated from the geometric mean of the last 6 reversals on a block of trials. Thresholds were measured at 4 different moving speeds of 1.25, 2.5, 5, and 10 deg/sec.
Results :
Compared to the normal, the subjects with abnormal degree of pattern glare showed significantly higher thresholds in detecting global motion at all 4 speeds tested (t-test, abnormal vs. normal: 0.29±0.13 vs. 0.17±0.05 at 1.25 deg/sec, p<0.01; 0.42±0.20 vs. 0.17±0.09 at 2.5 deg/sec, p<0.01; 0.53±0.19 vs. 0.18±0.08 at 5.0 deg/sec, p<0.01; 0.41±0.14 vs 0.18±0.04 at 10.0 deg/sec, p<0.01).
Conclusions :
People who are prone to pattern glare have reduced ability to detect global motion. This may provide new insights on understanding the neural mechanism of pattern glare.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.