Whitaker D, Mäkelä P, Rovamo J, Latham K
Department of Vision Sciences, Aston University, Birmingham, England.
Vision Res. 1992 Oct;32(10):1913-30. doi: 10.1016/0042-6989(92)90051-j.
The rate of decline with increasing eccentricity of several position and movement acuities was measured using a method of spatial scaling. In this method all stimuli at each visual field location are simply magnified versions of each other. The influence of separation and eccentricity were dissociated by presenting stimuli on an iso-eccentric arc. For each task, the rate of decline in performance was quantified by the parameter E2 which represents the eccentricity at which stimulus size must double in order to maintain performance equivalent to that at the fovea. All tasks were found to obey the concept of spatial scaling in that performance at a given field location could be equated with performance at any other location simply by a change of scale. However, the rate at which performance deteriorated with eccentricity varied over an enormous range (over 100-fold) depending on the task itself. The advantage of such diverse peripheral gradients is clear; the goal is to establish the physiological mechanisms which underlie this phenomenon.
使用空间缩放方法测量了几种位置和运动敏锐度随离心率增加的下降速率。在这种方法中，每个视野位置的所有刺激都是彼此的简单放大版本。通过在等离心率弧上呈现刺激来分离分离度和离心率的影响。对于每个任务，性能下降速率由参数E2量化，E2表示刺激大小必须加倍才能保持与中央凹处性能相当的离心率。发现所有任务都符合空间缩放概念，即给定视野位置的性能可以通过简单的比例变化与任何其他位置的性能等同。然而，性能随离心率恶化的速率根据任务本身在很大范围内（超过100倍）变化。这种多样的周边梯度的优势很明显；目标是确定这种现象背后的生理机制。
