STEREOPSIS, CYCLOTORSIONAL NOISE AND THE APPARENT VERTICAL
STEREOPSIS, CYCLOTORSIONAL NOISE AND THE APPARENT VERTICAL
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DOI：
10.1016/0042-6989(90)90029-k
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发表时间：
1990-01-01
期刊：
影响因子：
1.8
通讯作者：
ENRIGHT, JT
中科院分区：
文献类型：
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作者：
ENRIGHT, JT
原则上，立体视觉可以用来评估主观垂直的矢状面，但在回旋扭转的时间变化应降低的能力。在稳定的固定过程中的眼睛方向的视频记录被用来评估长期的不稳定性在旋转。在对同一目标进行约30次连续注视（持续5秒）期间，以1秒的间隔同时测量每只眼睛的扭转。对于每只眼睛来说，扭转平均值的标准差平均约为18分钟弧。一些这种变化是共轭的，但眼睛之间的扭转差异的变化平均为17分钟弧。大多数这种秒到秒的变化出现在固定之间（平均SD = 15分钟弧）。眼睛之间扭转差异的这种低频注视间变化必然在上下视野中产生虚假的水平视差，并且因此应该限制可以评估垂直单视界的精度。然而，在要求两个垂直分开的目标被调整到明显的等距离的性能测试中，所有的受试者都超过了精确度的理论极限，但只有在允许在上下目标之间来回移动注视的情况下。后者的结果提供了一个挑战，在目前的理解立体视觉。
In principle, stereopsis can be used to evaluate the subjective vertical in a sagittal plane, but temporal variation in cyclotorsion should degrade the ability. Video recordings of eye orientation during steady fixation were used to evaluate long-term instability in cyclotorsion. Torsion was measured simultaneously in each eye at 1-sec intervals during about 30 sequential fixations (5-sec duration) on the same target. For each eye separately, the standard deviation of torsion around its mean value averaged about 18 min arc. Some of this variation was conjugate, but the variability in torsional difference between the eyes averaged 17 min arc. Most of this second-to-second variation arose between fixations (average SD = 15 min arc). Such low-frequency inter-fixational variation in torsional difference between the eyes must produce spurious horizontal disparities in the upper and lower visual fields, and should thereby limit the precision with which the vertical horopter can be evaluated. All subjects exceeded those theoretical limits on precision, however, in performance tests requiring that two vertically separated targets be adjusted to apparent equidistance-but only when permitted to shift fixation back and forth between the upper and lower targets. That latter result provides a challenge in current understanding of stereopsis.