The purpose of this study was to develop an orientation and mobility
(O&M) assessment protocol to implement in subjects who have been implanted with an artificial silicon retina (ASR), and to use this experience to propose a research agenda for O&M with prosthetic vision
A controlled and naturalistic assessment was developed that included walking a prescribed obstacle course and travel to and from a hospital cafeteria. Subjects were tested before and 3 and 6 months after being implanted with the ASR. Outcome measures were walking speed and number of contacts with obstacles. The experiences from this study led to a proposed research agenda in O&M.
Eight subjects with retinitis pigmentosa participated in this study. The vision status of the subjects ranged from <20/1600 to 20/80 visual acuity and visual fields of <5 to 40°. Using a repeated-measures analysis of variance, no differences were found in the primary outcome measures. Four subjects were observed to have reduced mobility after implantation. Three subjects self-reported enhancements of travel after implantation, but this enhancement was not observed.
This study demonstrates that mobility might not be improved with prosthetic vision
. The proposed research agenda emphasizes the importance of developing individualized assessments, identifying specific items of orientation rather than mobility for measuring the effect of prosthetic vision
, and to develop and evaluate instructional programs that may be needed to obtain the full benefit of the technology.