Evaluation of Field Expansion for Acquired Monocular Vision with Multiplexing Prisms


Jung, J. - H., Castle, R., Kurukuti, N. M., Manda, S., & Peli, E. (2019). Evaluation of Field Expansion for Acquired Monocular Vision with Multiplexing Prisms. Investigative Ophthalmology & Visual Science , 60 (9), 4026-4026. Copy at https://tinyurl.com/yawks6oe


Individuals with acquired monocular vision (AMV) report collisions with pedestrians appearing in the temporal crescent of the blind eye. Our previous analyses show that loss of nasal field beyond ~55° may result in missing ~30% of possible collisions with other pedestrians. We developed a 3D-printed clip-on multiplexing prism (MxP) holder for AMV that expands nasal field ~30° into the missing temporal crescent. We evaluated pedestrian detection performance with the MxP in AMV using a virtual walking simulator. AMV was simulated with an eye patch in normal vision participants (N=8). Each subject was fitted with MxP in the 3D-printed clip-on holder. Visual fields were measured using the Goldmann perimeter for each viewing condition (normal, simulated AMV, and simulated AMV with MxP). Virtual walking scenarios were developed in a driving simulator, where pedestrians walked towards collision with the subject (walking speed 1.4m/s) from the left or right side with initial bearing angles of 45°, 65°, or 80°. Subjects fixated a target in the center of the screen and were to press the horn when they saw a pedestrian (48 trials per viewing condition). Detection rates and response times (between pedestrian appearance and horn press) were analyzed using a 3 (viewing condition)×6 (initial bearing) two-way repeated measures Analysis of Variance (ANOVA). The nasal field in simulated AMV expanded from 55.9°±1.5 to 81.3°±0.9 with the MxP. The ANOVA showed significant interaction between viewing condition and initial bearing for detection rate and response time (all p<0.001). Detection rate and response time on the blind nasal side of simulated AMV (61% with 4.1s at 65°; 50% with 5.1s at 80°) improved significantly (p<0.001) with MxP (94% with 1.8s at 65°; 64% with 4.1s at 80°) but was worse than normal vision (100% with 1.1s in 65°; 98% with 1.8s in 80°). Visual confusion caused by the MxP (superimposing seeing and shifted fields) did not interfere with detection performance at 45° since there were no significant differences in performance (all p=0.393) with normal vision (100% with 1.1s), simulated AMV (95% with 1.4s), and simulated AMV with MxP (100% with 1.2s). The 3D-printed clip-on MxP holder allowed for individualized prism fitting, which expanded visual field in simulated AMV and significantly improved pedestrian detection on the blind side with minimal interference in the seeing side. This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.