Stereopsis and Suppression in Strabismus and Amblyopia

摘要 弱视(懒眼)是一种视皮层神经发育障碍，发生在生命早期，影响 约占全球人口的3%。弱视与视力和对比度降低有关 非优势眼的敏感度。此外，大多数弱视患者没有 可测量的立体视觉或从双目信息感知深度的能力，这会产生负面影响 日常生活中的许多任务，包括眼手协调和导航。虽然研究表明，大约 25%的弱视人群确实有残留的立体视，调节这一功能的视网膜部位是 未知。这一建议验证了这样的假设，即当弱视患者出现立体视觉时，它是外围的。 而不是调节深度知觉的中心视野。第一个目标使用一种新的程序来绘制地图 中心和外围位置的立体视觉，以确定残余立体视觉是否确实是中介的 在外围。我们的实验数据表明，弱视的立体视觉是由外周调节的。我们会 还要确定这种外周立体视觉是否解释了融合会聚，即两者的运动 眼睛融合单目图像以形成双目感知。第二个目的是考察两者之间的关系 双眼条件下残留立体视和非优势眼抑制的文献记载 观看。我们将测量每个个体的抑制区，并将其与立体声缺乏区相关联 为同一个人测量的。参与者内部的这种比较对于理解关系是必不可少的 弱视患者这一特殊群体中的抑制和立体视觉缺陷之间的关系 立体视觉。这一群体约占屈光参差(不等屈光不正)患者的50%，约 10-40%的斜视患者(眼球偏斜)。这项研究将描述每个观察者的能力 包括周围视野的立体视觉，这在以前被忽略了。第三个目标将是 使用脑电(EEG)结合一种程序来定位产生 信号来理解有和没有立体视觉个体抑制的神经基础，以及有多好 非主导眼信号本身被表示，并且在另一只眼存在刺激的情况下，如 以及两只眼睛的信号在大脑皮层不同层次上是如何结合的。如果外围设备 视野对弱视的立体视有显著贡献，我们的研究将确定 临床评估外周立体视觉的潜力和训练外周位置以改善 立体视觉。

Abstract Amblyopia (‘lazy eye’) is a neuro-development disorder of the visual cortex that occurs early in life and affects about 3% of the population worldwide. Amblyopia is associated with reduced visual acuity and contrast sensitivity in the non-dominant eye. In addition, the majority of individuals with amblyopia do not have measurable stereopsis or the ability to perceive depth from binocular information, which negatively impacts many tasks of daily life including eye-hand coordination and navigation. While studies have shown that about 25% of the amblyopic population does have residual stereopsis, the retinal locus that mediates this function is unknown. This proposal tests the hypothesis that when stereopsis is present in amblyopia, it is the periphery and not the central visual field that mediates depth perception. The first aim uses a novel procedure to map stereopsis in both central and peripheral locations to determine whether residual stereopsis is in fact mediated by the periphery. Our pilot data suggest that it is the periphery that mediates stereopsis in amblyopia. We will also determine whether this peripheral stereopsis accounts for fusional vergence, the movement of the two eyes to fuse monocular images to form a binocular percept. The second aim examines the relation between residual stereopsis and the documented suppression of the non-dominant eye under conditions of binocular viewing. We will measure the suppression zone for each individual and relate it to the zone of stereo-deficiency measured for that same individual. This within-participant comparison is essential to understanding the relation between suppression and stereo-deficiency in this special group of amblyopic individuals who have residual stereopsis. This group comprises about 50% of those with anisometropia (unequal refractive error), and about 10-40% of those with strabismus (eye deviation). This study will characterize each observer’s capacity for stereopsis across the visual field including the periphery, which has been ignored previously. The third aim will use electroencephalography (EEG) combined with a procedure to localize cortical source that produces the signals to understand the neural basis of suppression in individuals with and without stereopsis, and how well the non-dominant eye signal is represented on its own, and in the presence of a stimulus in the other eye, as well as how the two eyes’ signals are combined at different levels of the cortical hierarchy. If the peripheral visual field has a significant contribution to stereopsis in amblyopia, our study will establish the importance of clinically evaluating the potential for stereopsis in the periphery and for training peripheral locations to improve stereopsis.