Limiting Factors on Spatial Vision in Central Vision Loss

描述（由申请人提供）：失去中心视觉的人经常发现很难用他们剩余的周边视觉来执行视觉任务。中央性视力丧失的主要原因是年龄相关性黄斑变性（AMD），这也是60岁以上人群视力受损的主要原因。中枢性视力丧失后，大多数患者在受影响的黄斑区域外出现视网膜偏心位置，即首选视网膜位点（PRL），作为其视觉任务的新参考位点。迄今为止，人们对PRL的性质知之甚少。本项目的长期目标是了解PRL发展的机制，了解PRL在各种视觉任务中的限制因素和潜力，以便为AMD和其他黄斑疾病患者制定有效的视觉康复策略。该研究项目的第一个目的是测试一个假设，即对于中心视力丧失的人来说，参考坐标从中央凹到PRL发生了转移。我们将测量几个动眼肌和知觉任务的视网膜轨迹，以确定每个任务的视网膜轨迹是否转移到暗斑外的偏心位置。我们还将比较相同的视网膜位点是否用于各种动眼肌任务和/或知觉任务。该研究项目的第二个目的是测试PRL的位置是基于具有最优视网膜结构和/或基本感知特性的位置的假设。我们将使用OCT获取视网膜的结构信息，并收集两个任务的功能数据，这些数据都是在每个观察者的暗点周围的多个视网膜位置

DESCRIPTION (provided by applicant): People who lose their central vision often found it difficult to perform visual tasks using their residual peripheral vision. The leading cause of central vision loss is age-related macular degeneration (AMD), which is also the leading cause of visual impairment for people over 60 years of age. Following the onset of the central vision loss, most patients develop an eccentric retinal location outside the affected macular area, the preferred retinal locus (PRL), as their new reference locus for visual tasks. To date, little is known about the properties of the PRL. The long-term goals of this project are to understand the mechanism(s) underlying the development of the PRL, and to understand the limiting factors and potentialities of the PRL(s) for various visual tasks so that effective visual rehabilitative strategies may be developed for patients with AMD and other macular disorders. The first aim of the proposed research project is to test the hypothesis that there is a shift in the reference coordinate from the fovea to the PRL for people with central vision loss. We will measure the retinal locus for several oculomotor and perceptual tasks to determine if the retinal locus for each task is shifted to an eccentric location outside the scotoma. We will also compare if the same retinal locus is used for various oculomotor tasks and/or perceptual tasks. The second aim of the proposed research project is to test the hypothesis that the location for a PRL is based on the location with the most optimal retinal structures and/or basic perceptual properties. We will obtain structural information of the retina using an OCT, and functional data will be collected for two tasks, all at multiple retinal locations around the scotoma of each observer with central vision loss. We will determine if the structural and/or functional data can predict the location of the PRL. The data will also tell us if there is a structure-function relationship of th retina around a scotoma. The third aim of the proposed research project is to test the hypothesis that for people with central vision loss, the benefits due to training can be enhanced by improving temporal processing and/or by improving fixation stability. We will develop a temporal training task and an oculomotor training task (fixational saccade adaptation), and to compare if these are more effective than the conventional spatial training task in improving functional vision for people with central vision loss. The findings from each of these aims have the potential of developing into a useful rehabilitative tool that can either help us identify the est location for a PRL for patients with recent onset central vision loss, or to improve the functional vision or reading performance in patients with central vision loss.