Time-to-Collision Estimation With Age-Related Macular Degeneration Using Visual and Auditory Cues: Which Cues are Most Important?

We measured time-to-collision (TTC) judgments from participants with age-related macular degeneration (AMD), and normal vision (NV) controls, with an audiovisual virtual reality system that simulated vehicles approaching in a 3D traffic environment. The vehicle was presented visually only, aurally only, or both simultaneously, allowing us to determine the relative importance of visual and auditory cues with psychophysical reverse correlation. Results indicated that TTC judgments were based on both auditory and visual cues in the AMD and NV groups; the AMD group relied, at least in part, on their residual vision. A multimodal advantage was not observed in either group. TTC estimation in the AMD group was surprisingly similar to that in the NV group. However, the AMD group showed a higher relative importance of "heuristic" cues compared to more reliably accurate cues favored by the NV group, suggesting that similar performance may be achieved through different cue-weighting strategies.