Field Expansion with Multiplexing Prism Glasses Improves Pedestrian Detection for Acquired Monocular Vision.

Purpose: 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.

IMPACT OF HEADLIGHT GLARE ON PEDESTRIAN DETECTION WITH UNILATERAL CATARACT.

Detecting pedestrians while driving at night is difficult, and is further impeded by oncoming headlight glare (HLG). Cataracts increase intraocular light scattering, making the task even more challenging. We used a within-subjects repeated measures design to determine the impact of HLG on driving with unilateral cataract. Pedestrian detection performance of six young normal vision (NV) subjects was measured with clear lens glasses and with simulated unilateral cataract (0.8 Bangerter foil) glasses. The subjects drove night-time scenarios in a driving simulator with and without custom simulated headlight glare. With simulated unilateral cataracts, pedestrian detection rates decreased and response times increased with oncoming HLG. We verified these effects with six patients who already underwent cataract surgery for one eye and were scheduled to get cataract surgery in the other eye. We measured their performance before and after the second cataract surgery. The results were similar to those obtained with the simulated unilateral cataract, confirming that a negative impact of HLG persists with untreated cataract in one eye.