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Nish Mohith Kurukuti, Kenny Tang, Jae-Hyun Jung, Eli Peli; Effect of peripheral prism configurations on pedestrian collision detection while walking. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2771.
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© ARVO (1962-2015); The Authors (2016-present)
Patients with homonymous hemianopia use superior and inferior peripheral (Peli) prisms to expand their visual field. Peripheral prisms are fitted with either horizontal or oblique (designed for driving) prism segments. Combinations of prism segments (configurations) can be used to detect potentially colliding pedestrians walking on their blind side. To find the best prism configuration for detecting such collisions, we used a geometric model to simulate collision scenarios and analyzed four configurations of 57Δ prisms: Horizontal in superior and inferior (HH), Oblique in superior and inferior (OO), Oblique in superior and Horizontal in inferior (OH), Horizontal in superior and Oblique in inferior (HO) (Fig.1).
The geometric model’s collision scenarios included 0.6m diameter pedestrians of 1-1.8m heights, approaching a collision point at different eccentricities (5-30°) and speeds (0.7-2m/s). A 0.6m diameter patient of 1-1.8m heights, looking at different viewing distances (3m ahead on the ground to straight ahead), approached the collision point at 1.4m/s. The entire collision scenarios take 6 seconds, during which the patient is wearing different peripheral prism configurations. The horizontal and oblique prism segments had a 20° vertical field of view, with horizontal prism starting from 20° in the superior/ inferior periphery and the oblique prism field of view starting from the horizontal midline (Fig. 1). We computed the collision detection rate with each configuration within 6s (total detections) and 3s (safe detections).
The OO configuration resulted in the best collision detections rate (99.8%), followed by OH (95.7%), HO (84.5%) and HH (42.6%) configurations in safe detections (Fig2). There was no large difference in the collision detection rate among configurations in total detections.
The OO configuration is better at detecting colliding pedestrians within a safe time.
This is a 2020 ARVO Annual Meeting abstract.
Figure 1: Peripheral prism configurations vertical coverage as a function of distance, from the patient fixating at the bold x. A video illustration can be found in the following link: https://youtu.be/YaWdkDYKJA8.
Figure 2: Pedestrian collision detection rate of peripheral prism configurations.
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