SIMULATION OF VISUAL IMPAIRMENT IN NORMAL SUBJECTS

空间对比敏感度与视野缺损的关系 使用人工暗点技术进行检查。 中心场对比度 在正常受试者中测量敏感性， 人工的，不同大小的中央暗点，并使用强迫选择 心理物理学方法 以前发现，对比度的类型 用5度光栅场观察到的灵敏度损失取决于 人工暗点的大小和与之相关的时间因素 刺耳的介绍。 小的人工暗点主要产生 高空间频率损耗。 较大的暗点产生了一个中等和低 通过开启光栅衬度而加剧的空间频率损耗 突然而不是逐渐地停止 在过去的一年里， 已经表明，当光栅场尺寸和 人工暗点尺寸增加了大约三倍。

The relationship between spatial contrast sensitivity and visual field loss was examined using an artificial scotoma technique. Central-field contrast sensitivity was measured in normal subjects both with and without artificial, central scotomata of varying sizes and using a forced-choice psychophysical method. Previously it was found that the type of contrast sensitivity loss observed with 5 degree grating field depended both on the size of the artificial scotoma and on temporal factors associated with grating presentation. Small artificial scotoma produced a predominatly high spatial frequency loss. Larger scotomata produced a middle and low spatial frequency loss which was acentuted by turning grating contrast on and off abruptly as opposed to gradually. Research during this past year, has shown that similar findings are obtained when grating field size and artificial scotoma size are increased by a factor of approximately three.