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

眼球运动在限制弱视空间视力中的作用

基本信息

批准号：
9806821
负责人：
Dennis Michael Levi
金额：
$ 22.46万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2021-08-31
项目状态：
已结题

项目摘要

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

莱维，丹尼斯·M. 项目概要/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，生命早期的屈光参差或形状剥夺会影响视力、对比敏感度和位置敏锐度。弱视在临床上很重要，因为除了屈光不正之外，它是视力丧失的最常见原因在婴儿和幼儿中，弱视引起了人们的基本兴趣，因为它反映了神经损伤，当正常视觉发育受到干扰时，就会发生这种情况。这项研究的长期目标是了解限制弱视人类空间视力的机制，最终目标是开发旨在更有效治疗的新方法。虽然我们过去研究的重点是感觉损失，但在这里我们建议应用许多创新方法将使我们能够测试有关眼球运动作用的具体假设限制弱视的空间视力。目标 1 检验以下假设：空间视觉异常至少部分是注视眼睛的结果具体来说，我们询问这些异常注视眼睛如何引起视网膜图像运动。运动以及眼球运动本身会影响视觉分辨率、视力、拥挤度和我们将使用高分辨率视频眼动仪 Tracking。扫描激光检眼镜 (TSLO) 可将刺激传送到精确可识别的位置在视网膜上，使用三种不同的方法来检验我们的假设：i）我们将测量、建模和描述正常和弱视成年人在执行视觉任务时的注视眼球运动 ii) 我们将通过比较视觉表现来评估视网膜图像运动的作用。在稳定、不稳定和“回放”（即叠加弱视眼的视网膜）下执行这些任务非弱视眼的图像运动）条件 iii) 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的视觉表现。与正常观察者相比，斜视性弱视者的扫视和手动能力明显更长目标 2 测试了他们的弱视眼看到的刺激的潜伏期。对于斜视性弱视，频繁的微扫视和伴随的扫视抑制和斜视患者努力保持弱视眼注视时的注意力转移，导致所有反应时间的类型不可减少地延迟，与不稳定的程度相称。不稳定程度与 LogMAR 敏锐度相关，因此反应时间和扫视潜伏期为还与 LogMAR 敏锐度相关，Aim 2 测试了一些关于作用的具体假设。反应时间和视觉搜索中的微扫视。 1