Tactile Cues for Improving Target Localization in Subjects with Tunnel Vision

The loss of peripheral vision is experienced by millions of people with glaucoma or retinitis pigmentosa, and has a major impact in everyday life, specifically to locate visual targets in the environment. In this study, we designed a wearable interface to render the location of specific targets with private and non-intrusive tactile cues. Three experimental studies were completed to design and evaluate the tactile code and the device. In the first study, four different tactile codes (single stimuli or trains of pulses rendered either in a Cartesian or a Polar coordinate system) were evaluated with a head pointing task. In the following studies, the most efficient code, trains of pulses with Cartesian coordinates, was used on a bracelet located on the wrist, and evaluated during a visual search task in a complex virtual environment. The second study included ten subjects with a simulated restrictive field of view (10°). The last study consisted of proof of a concept with one visually impaired subject with restricted peripheral vision due to glaucoma. The results show that the device significantly improved the visual search efficiency with a factor of three. Including object recognition algorithm to smart glass, the device could help to detect targets of interest either on demand or suggested by the device itself (e.g., potential obstacles), facilitating visual search, and more generally spatial awareness of the environment.