Bilateral retinal implants for improving visual restoration: a simulated bionic vision study

Degenerative diseases of the retina produce a severe deterioration in visual perception. Visual prostheses enable partial vision restoration by eliciting phosphenes (perceived spots of light) through electrical stimulation. By using augmented reality (AR) to simulate bionic vision (SBV), this study aims to provide insights on the potential benefits of bilateral retinal implants. While monocular implants have been extensively studied, research on binocular implants remains limited. Twenty-four volunteers participated in this study, and were divided into two groups, SBV-monocular and SBV-binocular groups; both experienced phosphene-based visual simulations of the scene using 120 phosphenes per implant. A control group perceived the scene directly through the cameras of the AR headset. Participants completed five tasks to assess their orientation, mobility, and pattern recognition capacities. SBV-binocular subjects outperformed in spatial perception and mobility tasks (p-value < 0.05), but not in pattern recognition tasks. All SBV groups perform significantly worse than the control group. The findings suggest that the bilateral implants’ enhanced field of view and stereoscopic depth cues afforded by bilateral implants were shown to support hand-eye coordination and spatial navigation tasks. However, relevant benefits were not demonstrated over monocular implants in detecting fine details in static tasks. This may be attributed to the absence of vergence control, the capacity to shift phosphene position in response to natural eye movements, in the bilateral configuration.