Reading in Peripheral Vision

描述（由申请人提供）：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，因此不得不使用周围视网膜。视力损害的主要原因是年龄相关性黄斑变性（AMD），这也是中央视力丧失的主要原因。本项目的长期目标是了解阅读周边视力的限制因素和潜力，以便为AMD和其他黄斑疾病患者制定有效的视力康复策略。该研究项目的第一个目的是评估一种假设，即中央视力丧失患者所采用的首选视网膜位点（PRL）或“伪中央凹”由于适应而表现出独特的中央凹样特性。将使用一组指标来衡量PRL的适应性，或“类似中央中心”的程度。这组指标包括注视和再注视的眼球运动特征、追求和扫视能力、阅读眼球运动、字母拥挤程度和阅读速度。测量将在AMD和Stargardt病患者中获得，并将与年龄匹配的正常视力对照观察者获得的类似测量结果进行比较。该研究项目的第二个目的是验证外周阅读缓慢是由于在外周阅读过程中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，以评估文本中连续的单词在空间和时间上分开是否可以提高阅读速度。该研究项目的第三个目的是验证以下假设：周边阅读之所以缓慢，是因为周边视觉中字母“特征”的整合受到了损害，尤其是当字母彼此靠近时，比如在单词中。一系列实验将在一组视力正常的观察者中进行，首先将比较识别单侧字母和侧边字母以及中央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，我们将识别那些字母特征！对信件识别很重要。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所需的字母特征的数量相比较，是否可以获得可比的中央凹和外围阅读速度。我们还将评估字母特征集成是否在一组AMD观察员中受损。

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.