The role of eye-movements in limiting spatial vision in amblyopia

作者声明：Dennis M. 项目摘要/摘要 弱视是一种空间视觉发育障碍，通常与斜视的存在有关， 早年屈光参差或形觉剥夺。它会影响视力、对比敏感度和位置敏感度。 弱视在临床上很重要，因为除了屈光不正外，它也是导致视力丧失的最常见原因 在婴幼儿中，弱视是基本感兴趣的，因为它反映了 当正常的视觉发育受到干扰时就会发生。这项研究的长期目标是 了解限制弱视患者空间视觉的机制，最终目标是 开发旨在更有效治疗的新方法。 虽然我们在过去的研究中的重点是感觉丧失，但在这里我们建议应用一种 一些创新的方法将使我们能够测试关于眼球运动作用的具体假设 弱视患者的空间视觉受限。 目标1测试了空间视觉异常至少部分是凝视眼睛的结果这一假设 动静。具体地说，我们问这些异常注视的眼睛是如何引起视网膜图像运动的 运动和眼球运动本身影响视觉分辨率、视觉敏锐度、拥挤和 空间定位的精确度和准确度。我们将使用高分辨率的视频眼球跟踪器，跟踪 扫描激光眼底镜(TSLO)，可将刺激传送到精确识别的位置 在视网膜上，使用三种不同的方法来验证我们的假设：i)我们将测量、建模和 描述正常和弱视成年人在执行下列视觉任务时的注视眼球运动 患有弱视。Ii)我们将通过比较视觉性能来评估视网膜图像运动的作用 在稳定、不稳定和回放(即，叠加弱视眼睛的视网膜)下的这些任务上 非弱视眼睛上的图像运动)。三)我们将通过以下方式评估眼球运动本身的作用 评估漂移和微扫视发生时间前后的视觉表现。 与正常观察者相比，斜视性弱视患者的眼球跳动时间和手动时间明显延长。 弱视患者的眼睛对刺激的潜伏期，与他们的同眼相比。《目标2》检验了这一假设 对于斜视性弱视，频繁的微扫视和伴随的眼跳抑制和 当斜视者努力保持对弱视眼睛的注视时，注意力的转移会导致所有 反应时间的类型是不可减少的延迟，与不稳定的程度相称。因为 不稳定程度与LogMAR视力相关，反应时间和眼跳潜伏期 也与LogMAR视力相关。Aim 2测试了一些关于 在反应时间和视觉搜索方面的微扫视。 1

Levi, Dennis M. PROJECT SUMMARY/ABSTRACT Amblyopia is a developmental disorder of spatial vision usually associated with the presence of strabismus, anisometropia or form deprivation early in life. It affects visual acuity, contrast sensitivity and position acuity. Amblyopia is clinically important because, aside from refractive error, it is the most frequent cause of vision loss in infants and young children, and amblyopia is of basic interest because it reflects the neural impairment which can occur when normal visual development is disrupted. The long-range objectives of this research are to understand the mechanisms that limit spatial vision in humans with amblyopia, with the ultimate goal of developing new approaches aimed at more effective treatment. While our focus in past studies has been on the sensory losses, here we propose the application of a number of innovative methods that will enable us to test specific hypotheses about the role of eye-movements in limiting spatial vision in amblyopia. Aim 1 tests the hypothesis that abnormal spatial vision is at least in part a consequence of fixational eye movements. Specifically we ask how both the retinal image motion induced by these abnormal fixational eye movements, and the eye movements per se, influence visual resolution, visual acuity, crowding and the precision and accuracy of spatial localization. We will use a high-resolution video eye tracker, the Tracking Scanning Laser Ophthalmoscope (TSLO) which allows stimuli to be delivered to precisely identifiable locations on the retina, to test our hypothesis using three different approaches: i) We will measure, model and characterize fixational eye movements in normal and amblyopic adults while performing visual tasks that are compromised in amblyopia. ii) We will assess the role of retinal image motion by comparing visual performance on these tasks under stabilized, unstabilized and “playback” (i.e., superimposing the amblyopic eye's retinal image motion on the nonamblyopic eye) conditions. iii) We will assess the role of eye movements per se by evaluating visual performance around the time of occurrence of drifts and microsaccades. Compared to normal observers, strabismic amblyopes have significantly longer saccadic and manual latencies to stimuli seen with their amblyopic eyes, compared to their fellow eyes. Aim 2 tests the hypothesis that for strabismic amblyopes, the frequent microsaccades and accompanying saccadic suppression and attentional shifts made while strabismics struggle to maintain fixation with their amblyopic eyes, result in all types of reaction times being irreducibly delayed, commensurate with the degree of unsteadiness. Because the degree of unsteadiness is correlated with LogMAR acuity, it follows that reaction time and saccadic latency are also correlated with LogMAR acuity. Aim 2 tests a number of specific hypotheses regarding the role of microsaccades in reaction time and visual search. 1