Design of 45∘ periscopic visual field expansion device for peripheral field loss

Patients with visual field loss have difficulty in mobility due to collision with pedestrians/obstacles from the blind side. In order to compensate for the visual field loss, prisms which deflect the field from the blind to the seeing side, have been widely used. However, the deflection power of current clinical Fresnel prisms is limited to ∼30°and only allows a 5°eye scanning range to the blind side. This is not sufficient to avoid most collisions and results in demands for a device with a higher power. In this paper, we propose a novel design and optimization of a higher power prism-like device (cascaded structure of mirror pairs filled with refractive medium) and verify enhanced field expansion of up to 45°in optical ray tracing and photorealistic simulations.