Reading in Peripheral Vision

University Of Houston, Houston TX

Investigators

Linked publications & trials

Abstract

[unreadable] 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. [unreadable] [unreadable]