Reading in Peripheral Vision

描述(申请人提供)：对于许多低视力患者来说，阅读是困难和缓慢的，特别是那些中央视网膜受损的患者，因此有义务使用他们的外围视网膜。导致视力损害的主要原因是老年性黄斑变性(AMD)，这也是导致中心性视力丧失的主要原因。该项目的长期目标是了解周边视力对阅读的限制因素和潜力，以便为AMD和其他黄斑疾病患者开发有效的视力康复策略。这项拟议的研究项目的第一个目的是评估这样一种假设，即中心性视力丧失患者采用的首选视网膜轨迹(PRL)或“假中心凹”由于适应而表现出独特的中心凹性质。一套衡量标准将被用来衡量PRL的适应程度，或者说“中心凹状”。这套指标包括注视和再注视的眼动特征、追逐和扫视能力、阅读眼球运动、字母的拥挤程度和阅读速度。将在AMD和Stargardt病患者中获得测量结果，并将其与年龄匹配、视力正常的对照观察者获得的类似测量结果进行比较。这项拟议研究项目的第二个目的是检验这一假说，即阅读缓慢是由于在阅读过程中到达同一视网膜位置的连续单词之间的时空交互作用增加。一系列实验将在视力正常的观察者和患有AMD的观察者身上进行测试，以评估当文本中连续的单词在空间和时间上分开时是否可以提高阅读速度。这项拟议研究项目的第三个目标是检验这一假设，即外围阅读速度慢是因为外围视觉中字母“特征”的整合受到损害，特别是当字母彼此靠近时，如单词。一系列实验将在一组视力正常的观察者身上进行，首先将比较识别单个字母和两侧字母以及中心凹和外围字母所需的特征数量。应用一种形式的反向相关分析，然后我们将识别这些字母特征THA！对于字母识别很重要。最后，我们将测试，如果我们将文本中字母特征的数量与各自偏心率所需的字母特征数量进行比较，是否可以获得类似的中心凹和外围阅读速度。我们还将评估患有AMD的一组观察者的字母特征整合是否受到损害。

DESCRIPTION (provided by applicant): Reading is difficult and slow for many low vision patients, especially those whose central retina is damaged, and thus are obligated to use their peripheral retina. The leading cause of visual impairment is age-related macular degeneration (AMD), which is also the leading cause of central vision loss. The long-term goal of this project is to understand the limiting factors and potentialities of peripheral vision for reading, so that effective visual rehabilitation strategies may be developed for patients with AMD and other macular disorders. The first aim of the proposed research project is to evaluate the hypothesis that the preferred retinal locus (PRL) or "pseudo-fovea" adopted by patients with central vision loss exhibit unique fovea-like properties as a result of adaptation. A set of metrics will be used to gauge how adapted, or "fovea-like", is the PRL. This set of metrics include oculomotor characteristics for fixation and refixation, pursuit and saccade ability, reading eye movements, extent of crowding for letters, and reading speed. Measurements will be obtained in patients with AMD and Stargardt's disease, and will be compared with similar measurements obtained in age-matched control observers with normal vision. The second aim of the proposed research project is to test the hypothesis that slow peripheral reading is due to the increased spatio-temporal interaction between successive words that arrive at the same retinal location during reading in the periphery. A series of experiments, to be tested in observers with normal vision and observers with AMD, will evaluate whether reading speed can be enhanced when successive words in text are separated both in space and time. The third aim of the proposed research project is to test the hypothesis that peripheral reading is slow because the integration of letter "features" is impaired in peripheral vision, especially when letters are presented close to one another, as in words. A series of experiments, to be performed in a group of observers with normal vision, will first compare the number of features required for identifying single vs. flanked letters, and in the fovea vs. the periphery. Applying a form of reverse-correlation analysis, we will then identify those letter features tha! are important for letter identification. Finally, we will test whether comparable foveal and peripheral reading speeds can be obtained if we scale the number of letter features in text with respect to the number of letter features required at the respective eccentricity. We will also evaluate if letter feature integration is impaired in a group of observers with AMD.