Patients with acquired monocular vision (AMV) lose vision in the temporal crescent on the side of the blind eye. This visual field loss affects patients'ability to detect potential hazards in the blind field. Mounting a base-in multiplexing prism (MxP) on the nasal side of the seeing eye can provide true field expansion and enable detection of potential collision hazards. We evaluated the efficacy of the MxP glasses in a virtual reality walking environment. Methods: A three-dimensional printed clip-on MxP holder that can be adjusted for an individual user's facial parameters was developed. Virtual reality walking scenarios were designed to evaluate the effect of MxP field expansion on the detection of a pedestrian approaching from different initial bearing angles and courses. The pedestrian detection rates and response times of 10 participants with simulated AMV (normally sighted participants with one eye patched) and three patients with AMV were measured. Results: The MxP provided true field expansion of about 25°. Participants performed significantly better with the MxP than without the MxP in the pedestrian detection task on their blind field, while their seeing field performance was not significantly different. Conclusions: The MxP glasses for patients with AMV improved the detection of potential collision hazards in the blind field. Translational Relevance: The MxP with an adjustable clip-on holder may help patients with AMV to decrease the risk of collision with other pedestrians.

Patients with visual field loss frequently collide with other pedestrians, with the highest risk being from pedestrians at a bearing angle of 45°. Current prismatic field expansion devices (≈30°) cannot cover pedestrians posing the highest risk and are limited by poor image quality and restricted eye scanning range (<5°). A new field expansion device: multi-periscopic prism (MPP); comprising a cascade of half-penta prisms provides wider shifting power (45°) with dramatically better image quality and wider eye scanning range (15°) is presented. Spectacles-mounted MPPs were implemented using 3D printing. The efficacy of the MPP is demonstrated using perimetry, photographic depiction, and analyses of the collision risk covered by the devices.

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