Abstract
Purpose: :
For those who are blind, the BrainPort® vision device enables perception of visual information using the tongue as a substitute for the eye. Users form a spatial reference with a few hours of training, mapping cutaneous information on the tongue to their environment. The following study demonstrates "visual skills" in acuity, object recognition, orientation and mobility provided by the BrainPort vision device.
Methods: :
9 profoundly blind subjects participated in the study, 4 had prior BrainPort exposure and 5 did not. Three skills were tested with the following performance goals: 1) FrACT "acuity" better than 20/600, 2) object location accuracy better than 70% and an object retrieval accuracy greater than 60%, 3) orientation and mobility accuracy of sign identification of 80% or better within 5 minutes per sign.
Results: :
8/9 subjects succeeded at the visual acuity test, 9/9 succeeded at both measures in the object recognition test, and 7/9 succeeded at sign identification portion of the orientation and mobility test. 5/9 subjects succeeded in finding the signs within the time limit. Users who did not achieve the success criterion returned for 30 minutes additional training. This brought overall performance to 8/9 subjects succeeding at both portions of the orientation and mobility test. Mean acuity across 9 subjects was equivalent to Snellen 20/100. Subjects mean object recognition (verbal location report) success rate was 98% and mean retrieval (first object touched) rate of 96% in the object recognition test. In the orientation and mobility test, during which the participants navigated a corridor and touched signs posted along the corridor, the subjects demonstrated a mean success rate of 87%.
Conclusions: :
As shown by these data, both new and experienced users demonstrated significant improvement in visual acuity, object location and grasping accuracy, and accuracy and speed of sign identification. 4/ 5 new and all 4 experienced users were able to achieve success on most criteria after 10 to 12 hours of training. As expected, experienced users performed better than the new users, as performance improves with increased experience with the device. These results confirm the BrainPort vision device as effective for its intended use.
Keywords: low vision • perception • plasticity