Functional impact of fixational eye movements in central vision loss

项目摘要/摘要 因老年性黄斑变性等黄斑疾病而丧失中央(中心凹)视力的人 或其他视网膜疾病通常患有视力不佳，无法通过光学、手术或 从治疗上讲。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 扭转视力下降的趋势。以前的努力是为了理解为什么视力对中心视力丧失的人来说如此困难 主要集中在与使用外围视网膜相关的空间特性上。这个项目考察了 还有一个不同的因素--凝视眼球运动的影响。大多数中心视力丧失的人都有 不稳定的注视，导致比视力正常的人更大的视网膜图像运动。这个 临床智慧是，夸张的凝视眼球运动对视力有害。真的是这样吗？人民 有中心性视力丧失的人必须使用他们的周边视力，因此，潜在的夸大凝视的眼睛 运动是有益的，因为它们可以防止外围视网膜上的图像褪色。这项研究将 首次尝试提供科学证据来理解凝视与眼球之间的关系 中心性视力丧失者的运动和功能视力。 这项拟议的研究项目的第一个目标是检验视网膜图像运动与 中心视力丧失的人表现出的凝视性眼球运动对他们来说是次优的，他们看起来很好 细节。我们将评估精细空间任务的性能如何随着视网膜图像运动量的变化而变化， 通过使用眼球跟踪扫描激光稳定(不同程度)视网膜上的刺激而产生的 检眼镜。我们预计，性能与视网膜图像运动量的对比将展示调谐： 太少的视网膜图像运动会导致视觉衰退(视力较差)和太多的视网膜图像运动 不利于观察空间细节。我们预测，对于任何特定的中心视力丧失的人， 存在一个产生最佳功能视力的最佳视网膜图像运动水平，这可能不符合 这是由于个体的自然注视眼球运动造成的。 这项拟议研究项目的第二个目标是检验这样一种假设，即由于 通过注视训练可以减少不正常的注视眼球运动。更重要的是，改进的 训练后的注视稳定性将伴随着功能视力的改善。我们会比较一下 在几个常见视觉任务上的性能，以及第一个目的中描述的调谐函数的形状， 在注视训练前后评价注视训练的效果。培训效果的保留 还将接受检查。 这个项目的发现将帮助我们理解凝视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和更有效的 改善中心性视力丧失患者功能性视力的康复方法或工具。

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.