Psychophysics of Reading - Normal and Low Vision

描述（申请人提供）：美国有330多万视力低下的人，其中大多数有阅读困难。许多人患有黄斑变性和相关的中央视力丧失。这项建议的主要目的是开发原则性的训练方法，以提高低视力阅读，特别是对于那些患有黄斑变性我们的研究表明，在视觉跨度的大小减少是一个关键因素，解释降低阅读速度在低视力。阅读的视觉广度是指在不移动眼睛的情况下可以准确识别的并排排列的字母的数量。视网膜的结构和中央视野的皮质放大产生小的视觉跨度，即使对于正常视力。这种小的视觉跨度是进一步减少作为一个结果的眼睛疾病。在一系列的心理物理学研究中，我们将建立在我们先前对视觉广度的研究基础上，开发原则性的训练方法来提高低视力阅读能力。要评估的三种形式的训练包括：1）垂直阅读，在垂直视觉跨度超过水平视觉跨度的情况下; 2）眼睛注视的视觉训练，以最大化通过视觉跨度的信息传递率;以及3）感知学习，其专注于扩大视觉跨度的大小。我们对决定视觉广度大小的感觉因素及其在阅读中的作用的探索将有助于阅读康复的应用。我们将研究空间因素（拥挤，位置的不确定性）和时间因素决定的视觉跨度在中央和周边视觉的大小。我们将使用功能磁共振成像定位的神经网站的文字和字母识别的视觉广度和知觉学习的影响，其大小。这些研究将告知我们的首选视网膜位点（PRL）的视觉处理能力的心理物理学探索，所述首选视网膜位点是许多患有黄斑变性的人用于阅读的周边视网膜区域。公共卫生相关性有超过330万美国人视力低下，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了解低视力人群的阅读困难。目前提案的一个主要目标是开发原则性的训练方法，以提高低视力阅读，特别是对黄斑变性患者。

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.