Indoor and outdoor navigation efficiency in older adults with and without age-related macular degeneration

Abstract

Purpose : Many visually impaired patients have trouble navigating, particularly in unfamiliar environments. Our study aimed to assess navigation efficiency in patients with age-related macular degeneration (AMD) and normally sighted individuals in unfamiliar outdoor and indoor environments.

Methods : Six AMD patients (68.8 ± 8.3 years) and 6 age-matched healthy controls (HC, 64.8 ± 6.6 years) completed two unfamiliar navigation routes (indoor and outdoor, each ~1 km). Participants guided-walked from a starting point to a designated location, then backtracked without guidance. Navigation efficiency was the ratio of backtracking and guided walking times, with larger ratio indicating less efficiency. Eye movements were recorded using Tobii Glass 3.0. Gaze parameters for each phase of each route were analyzed (e.g. average fixation duration, fixation rate, pupil size). The ratio of each gaze parameter within the backtracking and guided-walking phases were compared for each route.

Results : For the outdoor route, HC showed higher efficiency in navigation compared to AMD group (p=0.04). The ratio of fixation rates was negatively correlated with navigation efficiency in the HC group (r_s=-0.94, p=0.01), indicating that more fixations during navigation was associated with higher navigating efficiency. However, this correlation was not significant for the AMD group (r_s=-0.43, p = 0.40). For the indoor route, there was no significant difference in navigation efficiency between groups (p=0.86). Fixation duration ratios were negatively correlated with navigation efficiency for HC (r_s=-0.83, p=0.04), with longer fixation duration associated with more efficient navigation. Fixation duration ratios were not associated with navigation efficiency for the AMD group (r_s=-0.6, p=0.29).

Conclusions : As expected, navigation efficiency in an unfamiliar environment for the AMD group was poorer than HC. However, this effect was only evident for the outdoor route. Gaze parameters such as fixation rate and fixation duration might be related to more effective navigation in the HC. Findings suggest that AMD patients may use navigation strategies differently from healthy peers. Future research will investigate unique navigation strategies employed by individuals with AMD using a larger sample size.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.