Functional impact of fixational eye movements in central vision loss

项目总结/摘要 由于黄斑疾病（如年龄相关性黄斑变性）而失去中心（中央凹）视力的人 或其它视网膜疾病常常患有不能通过光学、手术或 治疗上到目前为止，黄斑疾病还没有有希望的治愈方法，也没有干预措施可以 逆转视力丧失。以前的努力，以了解为什么视力是如此困难的人与中央视力丧失 主要集中在与使用周边视网膜相关联的空间特性上。本项目研究 一个不同的因素-由于固定眼球运动的影响。大多数患有中央视力丧失的人 不稳定的固定，导致比正常视力的人更大的视网膜图像运动。的 临床经验认为，过度的注视性眼球运动对视力有害。真的是这样吗？人 中央视力丧失的人必须使用他们的周边视力，因此， 移动是有益的，因为它们防止周边视网膜上的图像褪色。这项研究将 首次尝试为理解注视与眼动之间的关系提供科学证据， 运动和功能性视力丧失的人。 该研究项目的第一个目的是验证视网膜图像运动与视网膜运动相关的假设。 中央视力丧失的人所表现出的注视眼球运动对于他们看到“精细”是次优的。 续费我们将评估精细空间任务的表现如何随着视网膜图像运动的量而变化， 通过使用眼睛跟踪扫描激光器稳定（在不同程度上）视网膜上的刺激而产生 检眼镜我们预计性能与视网膜图像运动量的关系将证明调谐： 视网膜图像运动太少会导致感知衰退（视力变差）和视网膜图像运动太多 这对观察空间细节是不利的。我们预测，对于任何一个有中心视力丧失的人， 存在产生最佳功能性视觉的视网膜图像运动的最佳水平， 这是由于个人的自然注视眼球运动。 拟议的研究项目的第二个目的是测试假设，视网膜图像运动，由于 通过注视训练可以减少不正常的注视眼运动。更重要的是， 训练后的固定稳定性将伴随着功能性视力的改善。我们将比较 在几个常见的视觉任务上的性能，以及如第一个目标中所述的调谐函数的形状， 在注视训练前后进行观察，以评估注视训练的效果。保持培训效果 也将被审查。 这个项目的发现将帮助我们理解注视性眼球运动在限制视力方面的作用， 中心视力丧失的人，以及我们如何利用这些信息来开发有用的，更有效的 康复方法或工具，以改善中心视力丧失患者的功能性视力。

PROJECT SUMMARY/ABSTRACT People who lose their central (foveal) vision due to macular disorders such as age-related macular degeneration or other retinal diseases often suffer from poor vision that cannot be corrected optically, surgically or therapeutically. To date, there is no promising cure for macular disorders, and there is no intervention that can reverse the vision loss. Previous efforts to understand why vision is so difficult for people with central vision loss have focused mainly on the spatial properties associated with using the peripheral retina. This project examines a different factor — the effects due to fixational eye movements. Most individuals with central vision loss have unsteady fixation, resulting in greater retinal image motion than that found in people with normal vision. The clinical wisdom is that exaggerated fixational eye movements are detrimental for vision. Is it really so? People with central vision loss must use their peripheral vision, therefore, potentially the exaggerated fixational eye movements are beneficial because they prevent images on the peripheral retina from fading. This research will be the first attempt in providing scientific evidence to understand the relationship between fixational eye movements and functional vision in people with central vision loss. The first aim of the proposed research project is to test the hypothesis that the retinal image motion associated with fixational eye movements exhibited by people with central vision loss is suboptimal for them to see “fine” details. We will evaluate how performance for fine spatial tasks changes with the amount of retinal image motion, generated by stabilizing (to different extent) a stimulus on the retina using an eye-tracking scanning laser ophthalmoscope. We expect that performance vs. the amount of retinal image motion would demonstrate tuning: Too little retinal image motion would cause perceptual fading (poorer vision) and too much retinal image motion would be detrimental for seeing spatial details. We predict that for any given individual with central vision loss, there is an optimal level of retinal image motion that yields the best functional vision, which may not correspond to that due to the natural fixational eye movements of the individual. The second aim of the proposed research project is to test the hypothesis that retinal image motion due to abnormal fixational eye movements can be reduced through fixation training. More importantly, the improved fixation stability after training will be accompanied by improvements in functional vision. We will compare performance on several common visual tasks, and the shape of the tuning function as described in the first aim, before and after fixation training to evaluate the efficacy of the fixation training. Retention of the training effect will also be examined. The findings from this project will help us understand the role of fixational eye movements in limiting vision for people with central vision loss, and how we can use the information to develop useful and more effective rehabilitative methods or tools to improve the functional vision for patients with central vision loss.