Psychophysics of Reading--Normal and Low Vision

描述(申请人提供)：美国有350多万低视力者，其中大多数人有阅读困难。这项建议的主要目的是评估视觉系统的知觉训练和可塑性对阅读康复的重要性，特别是对黄斑变性的人。我们的研究表明，视觉跨度的减小是导致低视力阅读速度减慢的关键因素。视觉跨度是指阅读过程中一眼就能识别出的字母数量。我们发现，在正常的周边视觉中进行知觉训练可以扩大视觉广度，并相应地提高阅读速度。在一系列心理物理研究中，我们将评估这一发现与视力正常和低视力的年轻人和老年人康复的相关性。我们还将探讨空间注意力和位置信号如何影响视觉跨度的大小。视力康复的潜力取决于眼睛疾病后视觉大脑的可塑性。在一系列fMRI实验中，我们将以低视力受试者为研究对象，1)评估视皮层视网膜定位的变化，2)询问视皮层是否参与触觉知觉。在第三系列中，我们将对来自白内障和黄斑变性患者的两大组特征良好的低视力阅读数据(MNREAD)进行二次分析。我们将利用这些数据来1)分析阅读视觉特性与视力障碍临床测量之间的关系；2)开发新的阅读能力量表来量化总体阅读能力；3)分析阅读能力与包括认知状态和心理健康状况在内的重要非视觉因素的关系。

DESCRIPTION (provided by applicant): There are more than 3.5 million Americans with low vision, most of whom have reading difficulties. The primary purpose of this proposal is to evaluate the importance of perceptual training and plasticity of the visual system to reading rehabilitation, particularly for people with macular degeneration.Our research indicates that decrease in the size of the visual span is a key factor explaining reduced reading speed in low vision. The visual span is the number of letters that are identified in a single glance during reading. We have found that perceptual training in normal peripheral vision can enlarge the visual span with a corresponding increase in reading speed. In a series of psychophysical studies, we will assess the relevance of this finding for rehabilitation in young and old subjects with normal and low vision. We will also ask how spatial attention and positional signals influence the size of the visual span.The potential for vision rehabilitation depends on the plasticity of the visual brain following eye disease. In a series of fMRI experiments, we will study low-vision subjects to 1) evaluate changes in retinotopic mapping in the visual cortex, and 2) ask whether visual cortex participates in tactile perception.In a third series, we will conduct secondary analyses on two large sets of well-characterized low-vision reading data (MNREAD) test), from cataract and macular-degeneration patients. We will use these data to 1) analyze the relationships between properties of reading vision and clinical measures of visual impairment; 2) develop a new reading ability scale for quantifying overall reading capacity, and 3) analyze the relationship between reading ability and important non-visual factors including cognitive status and mental-health status.