Monger Laura J, Shah Dhruvi, Wilkins Arnold J, Allen Peter M
Department of Vision and Hearing Sciences and Vision and Eye Research Unit, Anglia Ruskin University, Cambridge, UK.
Department of Psychology, University of Essex, Wivenhoe Park, Colchester, UK.
Clin Exp Optom. 2016 Jan;99(1):47-50. doi: 10.1111/cxo.12364.
We investigated whether symptoms of pattern glare were affected by viewing distance, as distinct from spatial frequency, because of an association between symptoms and anomalies of accommodation and vergence.
One hundred young adults viewed gratings with spatial frequencies of 0.3, 2.3 and 9.4 cycles per degree (cpd) at four test distances (0.4, 0.8, 1.6 and 3.2 metres). Participants were asked to grade the presence of 15 symptoms of visual perceptual distortions and discomfort, on a scale from zero (no symptoms) to 10 (maximum perceptual and somatic symptoms).
The viewing distance did not affect the nature and strength of symptoms, when viewing gratings with similar spatial frequencies. The symptoms increased with spatial frequency (p < 0.008 for all comparisons).
The symptoms from the Pattern Glare Test do not appear to be modulated by the changes in accommodation and vergence associated with viewing distance, at least in an unselected sample of students. The highest spatial frequency of the current Pattern Glare Test was 9.4 cpd at 0.4 metre and this is insufficiently high to measure the reduction in symptoms at high spatial frequencies. If assessing relative aversion to gratings of different spatial frequencies, it may be useful to increase the testing distance to 0.6 metre so as to increase the spatial frequency of the third grating to 14.2 cpd.
由于症状与调节和聚散异常之间存在关联，我们研究了图案眩光症状是否受观察距离影响，而非空间频率的影响。
100名年轻成年人在四个测试距离（0.4、0.8、1.6和3.2米）观看空间频率为0.3、2.3和9.4周/度（cpd）的光栅。要求参与者对15种视觉感知扭曲和不适症状的存在程度进行评分，评分范围为0（无症状）至10（最大感知和躯体症状）。
当观看具有相似空间频率的光栅时，观察距离不影响症状的性质和强度。症状随空间频率增加（所有比较p<0.008）。
至少在未经挑选的学生样本中，图案眩光测试的症状似乎不受与观察距离相关的调节和聚散变化的调节。当前图案眩光测试的最高空间频率在0.4米处为9.4 cpd，这一频率不够高，无法测量高空间频率下症状的减轻情况。如果评估对不同空间频率光栅的相对厌恶程度，将测试距离增加到0.6米可能有用，这样可以将第三个光栅的空间频率提高到14.2 cpd。
