Mitchell Donald E, Kennie Jan, Schwarzkopf D Samuel, Sengpiel Frank
Department of Psychology, Dalhousie University, Halifax, NS, Canada.
J Vis. 2009 May 21;9(5):22.1-7. doi: 10.1167/9.5.22.
Kittens reared with mixed daily visual input that consists of episodes of normal (binocular) exposure followed by abnormal (monocular) exposure can develop normal visual acuity in both eyes if the length of the former exposure exceeds a critical amount. However, later studies of the tuning of cells in primary visual cortex of animals reared in this manner revealed that their responses to interocular differences in phase were not reliable suggesting that their binocular depth perception may not be normal. We examined this possibility in 3 kittens reared with mixed daily visual exposure (2 hrs binocular vision followed by 5 hrs monocular exposure) that allowed development of normal visual acuity in both eyes. Measurements made of the threshold differences in depth that could be perceived under monocular and binocular viewing revealed a 10-fold superiority of binocular over monocular depth thresholds in one animal while the depth thresholds of the other two animals were poor and there was no binocular superiority. Thus, there was evidence that only one animal possessed stereopsis while the other two were likely stereoblind. While 2 hrs of daily binocular vision protected against the development of amblyopia, the poor outcome with respect to stereopsis points to the need for additional measures to promote binocular vision.
用混合的每日视觉输入饲养的小猫，即由正常（双眼）暴露期后接异常（单眼）暴露期组成，若前者暴露的时长超过临界量，两只眼睛都能发育出正常视力。然而，后来对以这种方式饲养的动物初级视皮层中细胞调谐的研究表明，它们对相位上的两眼差异的反应不可靠，这表明它们的双眼深度感知可能不正常。我们对3只通过每日混合视觉暴露饲养的小猫（2小时双眼视觉后接5小时单眼视觉）进行了研究，这种饲养方式使两只眼睛都能发育出正常视力。对单眼和双眼观察下可感知的深度阈值差异进行测量发现，一只动物的双眼深度阈值比单眼深度阈值优越10倍，而另外两只动物的深度阈值很差，不存在双眼优势。因此，有证据表明只有一只动物具有立体视觉，而另外两只可能是立体盲。虽然每天2小时的双眼视觉可防止弱视的发展，但在立体视觉方面的不良结果表明需要采取额外措施来促进双眼视觉。
