Braddick O
Department of Psychology, University College London, UK.
Eye (Lond). 1996;10 ( Pt 2):182-8. doi: 10.1038/eye.1996.45.
A variety of behavioural and electrophysiological studies agree that the onset of functional binocular interaction in human visual cortex normally occurs between 10 and 16 weeks of age. Measures of sensitivity to binocular correlation and to disparity agree closely, and behavioural and visual evoked potential measures on the same infant show onset of binocularity within about a 2 week range. Beyond the initial onset, the maximum disparity to which infants are sensitive increases steadily and stereoacuity is found to increase very rapidly. The initial development of binocularity does not appear to be a consequence of improving alignment of the eyes and occurs even in the presence of strabismus. However, the connections subserving binocularity are plastic in early childhood; they can be disrupted by unilateral strabismus, although in some strabismic children who use both eyes for fixation, they can adapt to serve stereo function at the angle of deviation and re-adapt, albeit temporarily, to the surgical alignment of the eyes. These findings allow us to pose some as yet unanswered questions about the development of binocularity, including: How is the infant's visual system organised before the establishment of binocularity? How does the pre-binocular infant maintain vergence? And what neural changes underlie the increase in performance for small and large disparities following the initial onset of binocular function?
各种行为学和电生理学研究均表明，人类视觉皮层中功能性双眼相互作用通常在10至16周龄之间开始。对双眼相关性和视差的敏感度测量结果高度一致，并且对同一婴儿进行的行为学和视觉诱发电位测量显示，双眼性在大约2周的范围内开始出现。在最初出现之后，婴儿敏感的最大视差稳步增加，并且发现立体视敏度增长非常迅速。双眼性的最初发展似乎不是眼睛对准改善的结果，甚至在存在斜视的情况下也会发生。然而，在儿童早期，支持双眼性的连接是可塑的；它们可能会被单侧斜视破坏，尽管在一些使用双眼注视的斜视儿童中，它们可以在斜视角度适应以发挥立体功能，并再次适应，尽管只是暂时的，眼睛的手术对齐。这些发现使我们能够提出一些关于双眼性发展的尚未得到解答的问题，包括：在双眼性建立之前，婴儿的视觉系统是如何组织的？双眼出现之前的婴儿如何保持辐辏？以及在双眼功能最初出现后，小视差和大视差表现增加的神经变化是什么？
