Reading in Peripheral Vision

描述（由申请人提供）：对于许多低视力患者，特别是那些中央视网膜受损的患者，阅读是困难和缓慢的，因此必须使用他们的周边视网膜。视力损害的主要原因是年龄相关性黄斑变性（AMD），其也是中心视力丧失的主要原因。本项目的长期目标是了解周边视觉阅读的限制因素和潜力，以便为AMD和其他黄斑疾病患者制定有效的视觉康复策略。拟议的研究项目的第一个目的是评估的假设，首选的视网膜位点（PRL）或“伪中央凹”，通过与中央视力丧失的患者表现出独特的中央凹样特性作为适应的结果。将使用一组指标来衡量PRL的适应性或“中央凹样”程度。这组度量包括注视和再注视的眼动特性、追踪和扫视能力、阅读眼动、字母拥挤程度和阅读速度。将在患有AMD和Stargardt病的患者中获得测量值，并将其与具有正常视力的年龄匹配的对照观察者中获得的类似测量值进行比较。所提出的研究项目的第二个目的是测试这一假设，即缓慢的周边阅读是由于在周边阅读期间到达相同视网膜位置的连续单词之间的时空相互作用增加。一系列的实验将在视力正常的观察者和患有AMD的观察者中进行测试，以评估当文本中连续的单词在空间和时间上分开时，阅读速度是否可以提高。拟议的研究项目的第三个目的是测试的假设，周边阅读是缓慢的，因为字母的“功能”的整合是受损的周边视觉，特别是当字母是接近彼此，如在单词。在一组视力正常的观察者中进行的一系列实验将首先比较识别单个字母与侧翼字母以及中央凹与周边字母所需的特征数量。应用一种形式的反向相关分析，然后我们将确定这些字母的功能，对字母识别很重要。最后，我们将测试是否可以获得可比的中央凹和周边阅读速度，如果我们缩放文字中的字母特征的数量相对于在各自的偏心率所需的字母特征的数量。我们还将评估一组AMD观察者的字母特征整合是否受损。

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.