Abstract
Purpose :
Because of compromised vision, visually impaired patients need to develop strategies to manage safe and efficient navigation that may increase cognitive load. We investigated how individuals with reduced vision utilized spatially salient information relative to normally sighted individuals during daily navigation and examined if different cognitive demands were required to complete this visually challenging task.
Methods :
Six individuals with normal vision (NV, 63.17 ± 6.31 years), six visually impaired patients due to age-related macular degeneration (AMD, 68.63 ± 8.28 years) as well as four more severely visually impaired patients (VI, 72.00 ± 5.37 years) were recruited to complete navigation tasks in real-world unfamiliar environments. Eye movements of three street crossing events for each participant were recorded using Tobii Glasses 3. Spatially salient areas (street zebra crossings, traffic light, and moving obstacles) were selected as areas of interest (AOIs). Gaze parameters (e.g. fixation duration and pupil diameter) within these AOIs were compared among groups.
Results :
All participants completed the street-crossing tasks successfully. We found significant main effect of group on maximum fixation duration on the selected AOIs (F = 6.21, p = 0.013, η2p = 0.489). Post-hoc analysis revealed a significant difference between AMD and NV groups (mean difference = 729.1 ms, p = 0.014), but not between the AMD vs. VI or the NV vs. VI groups. On average, the AMD group’s maximum duration fixation was 2.22 times larger than that of the NV group. However, no difference was found for the pupil diameter when participants fixated at the selected AOIs (F = 1.97, p = 0.179, η2p = 0.232).
Conclusions :
Our results showed that elderlies with reduced vision, particularly those having macular degeneration, required longer time to fixate at the spatially salient regions for safe street crossing. Intuitively, more cognitive resources are required for the visually impaired patients to deal with visually challenging events. However, a larger sample size is required to examine the differences in pupil diameter, another factor reflecting the cognitive loading during daily challenging navigation events.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.