Bradford School of Optometry & Vision Science, University of Bradford, Bradford, West Yorkshire, United Kingdom.
PLoS One. 2012;7(5):e36611. doi: 10.1371/journal.pone.0036611. Epub 2012 May 23.
Although their eyes are pointing in different directions, people with long-standing strabismic amblyopia typically do not experience double-vision or indeed any visual symptoms arising from their condition. It is generally believed that the phenomenon of suppression plays a major role in dealing with the consequences of amblyopia and strabismus, by preventing images from the weaker/deviating eye from reaching conscious awareness. Suppression is thus a highly sophisticated coping mechanism. Although suppression has been studied for over 100 years the literature is equivocal in relation to the extent of the retina that is suppressed, though the method used to investigate suppression is crucial to the outcome. There is growing evidence that some measurement methods lead to artefactual claims that suppression exists when it does not.
METHODOLOGY/RESULTS: Here we present the results of an experiment conducted with a new method to examine the prevalence, depth and extent of suppression in ten individuals with strabismic amblyopia. Seven subjects (70%) showed no evidence whatsoever for suppression and in the three individuals who did (30%), the depth and extent of suppression was small.
Suppression may play a much smaller role in dealing with the negative consequences of strabismic amblyopia than previously thought. Whereas recent claims of this nature have been made only in those with micro-strabismus our results show extremely limited evidence for suppression across the central visual field in strabismic amblyopes more generally. Instead of suppressing the image from the weaker/deviating eye, we suggest the visual system of individuals with strabismic amblyopia may act to maximise the possibilities for binocular co-operation. This is consistent with recent evidence from strabismic and amblyopic individuals that their binocular mechanisms are intact, and that, just as in visual normals, performance with two eyes is better than with the better eye alone in these individuals.
尽管患有长期斜视性弱视的人的眼睛指向不同的方向，但他们通常不会经历复视，也不会出现任何由斜视性弱视引起的视觉症状。人们普遍认为，抑制现象在处理弱视和斜视的后果方面起着重要作用，通过阻止来自较弱/偏离的眼睛的图像进入意识。因此，抑制是一种非常复杂的应对机制。尽管抑制现象已经研究了 100 多年，但关于被抑制的视网膜的范围，文献存在争议，尽管用于研究抑制的方法对结果至关重要。越来越多的证据表明，一些测量方法会导致人为的结论，即当抑制不存在时，它实际上是存在的。
方法/结果：在这里，我们展示了一项使用新方法检查 10 名斜视性弱视患者的抑制流行程度、深度和范围的实验结果。7 名受试者（70%）没有任何抑制的证据，而在另外 3 名受试者（30%）中，抑制的深度和范围很小。
与之前的想法相比，抑制在处理斜视性弱视的负面影响方面可能作用较小。虽然最近有类似的说法仅在那些有微斜视的人中提出，但我们的结果表明，在斜视性弱视者中，中央视觉场中抑制的证据非常有限。我们认为，斜视性弱视者的视觉系统可能不是通过抑制来自较弱/偏离的眼睛的图像，而是通过最大化双眼合作的可能性来发挥作用。这与斜视性和弱视性个体的最近证据一致，即他们的双眼机制完好无损，并且与视觉正常者一样，在这些个体中，双眼的表现要好于单眼。
