Oculomotor Strategies in Central Field Loss

Smith-Kettlewell Eye Research Institute, San Francisco CA

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Abstract

? DESCRIPTION (provided by applicant): Age-related macular degeneration is the most common cause of vision loss in the central portion of the retina, making central field loss a major problem in the world today. Eye movements essential for everyday tasks are largely reliant on the central retina in humans. As a result, patients with central field loss have poor visual acuity and impaired eye movements, which causes difficulty with reading and facial recognition. Many studies have systematically examined fixation stability in individuals with central field loss and few of these have even looked at saccadic eye movements responsible for target acquisition. To date, however, no study has systematically measured smooth pursuit in these individuals, despite its importance for tracking moving targets. The smooth pursuit system is particularly affected because the patient's central scotoma occludes the target of interest and because the patients' perception of this event may be altered as they are typically unaware of the size, location and even presence of their scotoma. To that end, we propose to study the perception and pursuit of motion in patients with central field loss, as well as in healthy subjects with artificial scotomas that can be precisely controlled for size and location. Because the properties of the patients' binocular vision are further complicated by the discrepant sizes and locations of the scotomas in the two eyes, we propose to conduct the smooth pursuit experiments during both binocular and monocular pursuit.