Perceptual mechanisms underlying reading difficulties in glaucoma

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PROPJECT SUMMARY Primary open angle glaucoma (POAG), characterized by progressive neurodegeneration of retinal ganglion cells and associated visual field defects, is a leading cause of blindness in the United States. The predominant view has been that glaucoma spares central visual function until the end-stages. However, accumulating evidence shows that the macula is involved in even early glaucomatous damage, including a significant reduction in retinal nerve fiber layer and/or ganglion cell layer thickness. In parallel with physiological evidence, behavioral evidence shows that functional deficits in various central vision tasks, such as reading and face recognition, often appear in individuals with glaucoma. Surprisingly, reading problems have been cited as a main source of anxiety among people with glaucoma. However, at present, we have no understanding of how glaucomatous damage impedes pattern recognition in the assumed-to- be-preserved central visual field. Nor do we know of effective means to alleviate these deficits. Even when treatment controls disease progression, individuals with existing visual field defects need to cope with compromised vision. Therefore, understanding the mechanisms limiting everyday visual function in glaucoma is important from both clinical and basic science perspectives. The proposed study will build on the empirical findings from our preliminary work and theoretical work from several decades of human pattern vision in order to make fundamental advances in our understanding of central visual function of glaucoma. The major goals of the proposed research are to understand how glaucoma undermines central pattern vision and to apply this knowledge to guiding the development of effective rehabilitative strategies to optimize the remaining vision of people with glaucoma. In particular, our specific aims are (1) To understand the impact of glaucomatous damage on central pattern recognition, (2) To understand the role of the spatial pattern of visual field defects, (3) To apply perceptual learning to reading rehabilitation of individuals with glaucoma. To date, very little attention has been paid to such research. The outcome of the current research proposal is expected to help us understand the limiting factors underlying daily visual function in glaucoma and identify potential rehabilitative interventions. Furthermore, the knowledge obtained from the proposed research will provide new insights on how retinal ganglion cell pathology affects human pattern recognition.