Low Vision and Brain Plasticity

摘要

Evidence for the functional reorganization of visual brain areas in blind people provides compelling examples of brain plasticity associated with visual impairment. But what sorts of plasticity are present in cases of low vision? a??Low visiona?? refers to any long-term visual deficit, not correctable by lenses, affecting everyday visual function while preserving some level of useful vision. In cases of low vision, visual cortex still participates in visual processing, but with abnormal input, characterized clinically as reduced acuity, reduced contrast sensitivity, and/or visual-field loss. What sorts of plastic changes in the visual pathway accompany these three types of vision loss? What are the behavioral consequences of these changes? What is the impact of the age of onset of low vision on plasticity? I will discuss these unresolved questions, using examples of psychophysical and fMRI studies from my research. An important example is macular degeneration. This common eye disease often results in central-field loss, requiring the use of peripheral vision for reading and other tasks usually mediated by central vision. I will also address the relevance of research on low-vision plasticity for rehabilitation.