Age-related macular degeneration (AMD) is a leading cause of visual impairment in our elder population. In healthy vision, the fovea plays a critical role in gathering high resolution information about the visual world. We use this information for localizing objects during the preparation and execution of reaching movements. When the fovea and surrounding tissues cease to function, a blindspot (or scotoma) occurs in central vision, and AMD patients must adopt new eye-hand coordination strategies. Most research in eye movement control for AMD patients has concentrated on "eccentric viewing" (i.e. using peripheral vision to see objects) and on reading strategies. Almost no research has been conducted on the important adaptations that must take place for eye-hand coordination to be effective in daily tasks, such as making a sandwich or pouring a cup of tea. As we develop our understanding of adaptations that benefit (or impair) functional outcome for AMD patients, we can utilize this information to improve rehabilitation programs. The work in this proposal is divided into three aims. The first examines to what extent reaching delays and errors can be attributed to normal acuity decline in the periphery. The second examines how central field loss contributes to misdirected eye movements that impair eye-hand coordination.
The third aim examines whether and how oculomotor and reaching adaptation occurs as a function of age and disease duration. We will construct a dataset on reaching and eye movements collected from normal, AMD and juvenile macular degeneration (JMD) observers over a large age range (40-100). We will share this dataset publicly so that we and others may use it as a resource to investigate the factors of age, disease and adaptive strategies on eye- hand coordination. The outcomes of this study will further our understanding of the functional impact of central field los, and will also be of significance to basic researchers in sensorimotor integration.
Age-related macular degeneration is a significant public health issue - it is the leading cause of reduced visual function in elders that cannot be corrected optically. This proposal seeks to quantify reaching behaviors in patients with central field loss due to maculopathy, and to determine how age, degree of visual impairment, oculomotor control and eye-hand coordination all contribute to the deficit. This is the first complete scientific study of these behaviors and will necessarily inform our approach to low vision rehabilitation, in addition to providing a rich dataset for further analysis among the scientific community.