Abstract
Night blindness impairs patients' ability to venture outdoors independently after sunset. High sensitivity cameras provide an opportunity to develop visual aids. Unlike military night vision devices (designed for total darkness) these devices will be used in highly light-variable environments. We surveyed urban and suburban light levels and measured the effect of light reductions on patients' visual acuity, contrast sensitivity and visual field. An augmented night vision see-through device we are developing is designed to provide users two options, using their natural vision multiplexed with a visual field expanding contour image in brighter environments, or viewing enhanced video image in darker areas. The most relevant measurements to assess the potential value of such a device are not known; therefore we have used a variety of mobility measures and performance tasks in our pilot studies, which include an indoor dense obstacle course and on-the street assessments. Because patients would have benefited from longer-term adaptation to the device (including integration with long cane use) than was possible in early pilots; a small study is currently underway in which 4 patients are using 2 different devices for 2 weeks at home. Results of the indoor and pilot outdoor studies will be reported.
Supported by NIH grants EY12890 and EY12912