Department of Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK.
NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK.
Proc Biol Sci. 2020 May 27;287(1927):20200607. doi: 10.1098/rspb.2020.0607. Epub 2020 May 13.
The human visual field, on the temporal side, extends to at least 90° from the line of sight. Using a two-alternative forced-choice procedure in which observers are asked to report the direction of motion of a Gabor patch, and taking precautions to exclude unconscious eye movements in the direction of the stimulus, we show that the limiting eccentricity of image-forming vision can be established with precision. There are large, but reliable, individual differences in the limiting eccentricity. The limiting eccentricity exhibits a dependence on log contrast; but it is not reduced when the modulation visible to the rods is attenuated, a result compatible with the histological evidence that the outermost part of the retina exhibits a high density of cones. Our working hypothesis is that only one type of neural channel is present in the far periphery of the retina, a channel that responds to temporally modulated stimuli of low spatial frequency and that is directionally selective.
人类的视野在颞侧至少可以扩展到视线外 90°。我们使用了一种二选一的强制选择程序，要求观察者报告一个 Gabor 补丁的运动方向，并采取预防措施排除刺激方向上无意识的眼球运动，从而精确地确定了成像视觉的极限视场。在极限视场上存在着很大但可靠的个体差异。极限视场显示出对对数对比度的依赖性；但是当可见的杆状细胞调制减弱时，它不会减少，这一结果与组织学证据一致，即视网膜的最外层表现出高浓度的锥体。我们的工作假设是，只有一种神经通道存在于视网膜的远周边，该通道对低空间频率的时变调制刺激做出反应，并且具有方向选择性。
