School of Health Sciences, The Henry Wellcome Laboratories for Vision Science, Centre for Applied Vision Research, University of London, London, United Kingdom.
Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, Telangana, India.
PLoS One. 2023 Jan 24;18(1):e0280785. doi: 10.1371/journal.pone.0280785. eCollection 2023.
Binocular summation of luminance contrast signals in the spatial domain has been investigated in many studies, but less attention has been paid to the analogous interactions in the temporal domain. The present study determined the impact of monocular sensitivity on the binocular detection of luminance-modulated flickering stimuli. Binocular summation ratios (BSRs) were determined in 13 visually-normal adults for a range of monocular flicker modulation thresholds (FMTs), generated by changing stimulus size (7'- 60') and luminance (mesopic and photopic). Monocular and binocular FMTs were measured at the point of regard and in each of the four quadrants at 5° eccentricity for each target size and luminance using the Flicker-Plus test. Monocular and binocular FMT's increased with decreasing target size for all retinal locations (p<0.001), and were overall larger for mesopic than for photopic condition (p<0.001). BSRs for mesopic (mean±SD: 1.50±0.21) and photopic (1.60±0.24) stimuli were greater than unity (p<0.001), with the latter showing larger estimates than former (p<0.001). BSRs showed no significant trend across target sizes for both luminance conditions (p>0.12). The results demonstrate that the visual system successfully summates inputs from the two eyes to enhance flicker detection, independent of their absolute monocular detection thresholds. These findings may serve as a predictive baseline for further experiments designed to determine how other stimulus properties and interocular differences in monocular thresholds may affect the binocular perception of flicker.
在许多研究中，已经研究了空间域中亮度对比度信号的双目总和，但对时间域中类似的相互作用关注较少。本研究确定了单眼敏感性对亮度调制闪烁刺激的双眼检测的影响。在 13 名视力正常的成年人中，确定了一系列单眼闪烁调制阈值（FMT）的双眼总和比（BSR），通过改变刺激大小（7'-60'）和亮度（中间和明视）来产生。使用 Flicker-Plus 测试，在注视点和每个目标大小和亮度的每个目标大小和亮度的 5°偏心处的四个象限中测量了单眼和双眼 FMT。对于所有视网膜位置（p<0.001），随着目标大小的减小，单眼和双眼 FMT 均增加，并且在中间亮度条件下总体上大于明视（p<0.001）。中间亮度（均值±SD：1.50±0.21）和明视（1.60±0.24）刺激的 BSR 大于 1（p<0.001），后者的估计值大于前者（p<0.001）。对于两种亮度条件，BSR 均未显示出随目标大小的明显趋势（p>0.12）。这些发现表明，视觉系统成功地将来自两只眼睛的输入总和起来，以增强闪烁检测，而与它们的绝对单眼检测阈值无关。这些发现可以作为预测基线，用于进一步实验，以确定其他刺激特性和单眼阈值中的双眼差异如何影响闪烁的双眼感知。
