Psychophysics of Reading - Normal and Low Vision

描述(申请人提供)：美国有330多万低视力者，其中大多数人有阅读困难。许多人患有黄斑变性和相关的中心视力丧失。这项建议的主要目的是开发有原则的训练方法来提高低视力阅读，特别是对于那些患有黄斑变性的人。我们的研究表明，视觉广度的减小是导致低视力阅读速度减慢的一个关键因素。阅读的视觉跨度是指在不移动眼睛的情况下，可以准确识别的字母的数量，如文本中并排排列的字母。即使是正常视力，视网膜的结构和中央视野的皮质放大也会产生较小的视野范围。由于眼病，这种小的视觉范围会进一步缩小。在一系列的心理物理学研究中，我们将在我们之前对视觉广度的研究的基础上，开发出原则性的训练方法来提高低视力阅读。要评估的三种训练形式包括：1)在垂直视觉跨度超过水平视觉跨度的情况下进行垂直阅读；2)眼睛注视的眼球运动训练，以最大限度地提高通过视觉跨度的信息传递率；以及3)知觉学习，其重点是扩大视觉跨度的大小。我们探索决定视觉广度大小的感觉因素及其在阅读中的作用，将有助于阅读康复的应用。我们将检查空间因素(拥挤、位置不确定)和时间因素，这些因素决定了中央和外围视觉的视觉跨度大小。我们将使用fMRI来定位视觉范围内单词和字母识别的神经位置以及知觉学习对其大小的影响。这些研究将为我们探索首选视网膜位置(PRL)的视觉处理能力提供心理物理方面的信息，PRL是许多黄斑变性患者用于阅读的外围视网膜区域。与公共健康相关美国有330多万视力低下的人，其中大多数人有阅读困难。我们的广泛目标是利用视觉科学的发现来理解视力低下者的阅读困难。目前这项提议的一个主要目标是开发有原则的训练方法来提高低视力阅读，特别是对于黄斑变性患者。

Description (provided by applicant): There are more than 3.3 million Americans with low vision, most of whom have reading difficulties. Many suffer from macular degeneration and associated loss of central vision. The primary purpose of this proposal is to develop principled training methods to enhance low-vision reading, particularly for those 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 for reading refers to the number of letters, arranged side-by-side as in text that can be recognized accurately without moving the eyes. Structure of the retina and cortical magnification of the central visual field produce a small visual span, even for normal vision. This small visual span is further diminished as a consequence of eye disease. In a series of psychophysical studies, we will build on our prior research on the visual span to develop principled training methods to enhance low-vision reading. The three forms of training to be evaluated include: 1) Vertical reading in cases where the vertical visual span exceeds the horizontal visual span; 2) Oculomotor training of eye fixations to maximize the information transfer rate through the visual span; and 3) Perceptual Learning which is focused on enlarging the size of the visual span. The applications to reading rehabilitation will benefit from our exploration of the sensory factors determining the size of the visual span and its role in reading. We will examine spatial factors (crowding, positional uncertainty) and temporal factors determining the size of the visual span in central and peripheral vision. We will use fMRI to localize the neural site of word and letter recognition within the visual span and the influence of perceptual learning on its size. These studies will inform our psychophysical exploration of the visual- processing capacity of the preferred retinal locus (PRL), the region of peripheral retina used for reading by many people with macular degeneration. PUBLIC HEALTH RELEVANCE There are more than 3.3 million Americans with low vision, most of whom have reading difficulties. Our broad goal is to use findings from vision science to understand the reading difficulties of people with low vision. A major goal of the current proposal is to develop principled training methods to enhance low-vision reading, particularly for people with macular degeneration.