Standardizing Visual Rehabilitation using Simple Virtual Tests

Many different visual rehabilitation approaches are being utilized to offer visual information to the blind. User proficiency and functional ability are currently evaluated either via ad-hoc tests or via standardized visual tests which are not sensitive enough in the range of extreme low vision. Unfortunately, this is the functional level that these approaches typically offer. This is especially important as the main criteria by which most users will judge the efficacy of these rehabilitation approaches is by the functional benefits it grants them. Furthermore, currently, there are no accepted benchmarks or clear comparative testing of each rehabilitation approach, leading to the development of many new aids but the practical adoption of few. Combined these indicate a need to add standardized functional tests to this evaluation toolbox. Indeed, several functional tests have recently been suggested but their adoption has been very limited. Here, we review current tests and then conduct a formative study consulting experts in the field to map issues with current standardization attempts. This formative study offered a list of practical design suggestions for functional standardization tests. We then suggest using simple virtual environments as one such family of tests. Virtual scenarios meet many of the experts' suggestions - they are easy to share, flexible, affordable, safe, identical wherever run, can be run by a single operator and offer control over external parameters enabling a focus on the offered visual information. Finally, we demonstrate this approach via a freely available virtual version of a relatively standard functional test - finding a door - in a 10-minute paradigm which includes 30 trials. We find that congenitally-blind and sighted-blindfolded subjects cannot perform this task without the device, but that they perform it successfully with it, demonstrating the tests' potential viability.