Morisita M, Yagi T
Department of Otolaryngology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603, Tokyo, Japan.
Auris Nasus Larynx. 2001 Nov;28(4):301-4. doi: 10.1016/s0385-8146(01)00100-6.
The stabilization of eye movements during voluntary fixation is believed to depend upon the visual feed back, since gaze becomes less stable in the darkness. The temporal variability of human eye orientation in both the horizontal and vertical direction is typically no more than a few minutes of arc. Ocular stability in terms of torsion has, however, been less understood.
In this study, the stability of gaze in the three dimensions (horizontal, vertical, and torsional) was investigated using a video image analysis system. In ten healthy subjects, eye movements were recorded after fixating the eye on a target in the light and also in the dark (imaginary target). The standard deviations of the eye movements in the three dimensions were calculated during fixation.
In the light, the horizontal and vertical eye movements exhibited an alternating sequence of a slow drift and resetting microsaccades, as previously reported. The torsional eye movements, however, showed no such drifts and resetting. In the dark, the horizontal and vertical eye movements exhibited about 2-3 times larger value of the standard deviation than that in the light. In contrast to this, the difference in the standard deviation between the light and dark was not so prominent in case of the torsional eye movement as compared to those of horizontal and vertical.
These results support the idea that information from the peripheral retina does not significantly influence the feed back system for fixating the target in the light.
由于在黑暗中注视变得不太稳定，因此人们认为在自主注视过程中眼球运动的稳定依赖于视觉反馈。人眼在水平和垂直方向上的时间变异性通常不超过几分弧度。然而，关于眼球扭转方面的稳定性了解较少。
在本研究中，使用视频图像分析系统研究了三维（水平、垂直和扭转）注视的稳定性。在10名健康受试者中，在明亮环境中以及黑暗环境（想象中的目标）中将眼睛注视在目标上后记录眼球运动。在注视期间计算三维眼球运动的标准差。
在明亮环境中，水平和垂直眼球运动呈现出缓慢漂移和复位微扫视的交替序列，如先前报道的那样。然而，扭转眼球运动并未表现出此类漂移和复位。在黑暗环境中，水平和垂直眼球运动的标准差比在明亮环境中大约大2 - 3倍。与此形成对比的是，与水平和垂直眼球运动相比，扭转眼球运动在明亮和黑暗环境中标准差的差异并不那么显著。
这些结果支持这样一种观点，即来自周边视网膜的信息在明亮环境中对注视目标的反馈系统没有显著影响。
