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The normal visual system provides a wide field of view apparently at high resolution. The wide field is continuously
monitored at low resolution for navigation and detection of objects of interest. These objects are sampled using the high-resolution
fovea, applying a temporal multiplexing scheme. Most vision impairments that cause low vision impact upon
only one of the components; the peripheral low-resolution wide field or the central high-resolution fovea. The loss of one
of these components prevents the interplay of central and peripheral vision needed for normal function and causes
disability. Traditional low-vision aids improve the impacted component, but usually at a cost of a significant loss in the
surviving component. For example, magnifying devices increase resolution but reduce the field of view, while minifying
devices increase the field of view but reduce resolution. A general optical engineering approach - vision multiplexing
- is presented. Vision multiplexing seeks to provide both the wide field of view and the high-resolution information in
ways that could be accessed and interpreted by the visual system. The use of various optical and electro-optical methods
in the development of a number of new visual aids, all of which apply vision multiplexing to restore the interplay of
high-resolution and wide-angle vision using eye movements in a natural way, will be described. Vision-multiplexing
devices at various stages of development and testing illustrate the successes and difficulties in applying this approach for
patients with tunnel vision, hemianopia (half blindness), and visual acuity loss (usually due to central retinal disease).
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