Abstract
Purpose :
Visual cancellation tasks evaluate how individuals identify relevant information among clutter. This work examined how visual search is affected by healthy aging and AMD in the Bells test cancellation task.
Methods :
98 participants from the SilverSight French cohort were included in this study: 43 young adults (YA, 30 ± 4.8 years), 12 middle-aged adults (MA, 51.2 ± 5.9 y), 36 older adults (OA, 74.4 ± 4.4 y), and 7 individuals with AMD (78.6 ± 7.8 y). Participants had to find and cancel 35 bell symbols among 280 distractors while wearing a mobile eye-tracker. We examined the number of cancellations, test duration, the time and distance between cancellations, search efficiency (Q-score) and organization (Best-R). Fixation number, duration and dispersion, inter-fixation duration and distance as well as scan-path metrics were extracted from gaze data. All save the AMD group underwent a visuo-cognitive screening, including UFOV, TMT, figural and working memory tests.
Results :
OA made fewer cancellations than YA and were less efficient than both YA and MA groups (lower Q-score). Successive cancellations of OA were further apart in both time and space, compared to YA. OA were also slower than YA to complete the test and more variable than YA in both inter-cancellation time and distance. OA made more fixations and showed longer scan-path lengths, compared to YA. All healthy participants showed similar search orders (Best-R values), fixation duration and dispersion, inter-fixation time and distance, and % of the scene covered during the search. Search efficiency and test duration correlated significantly with selective visual attention (UFOV 3), processing speed (TMT part A), figural memory, and working memory span.
AMD patients had lower performance, compared to age-matched visually healthy subjects, on the cancellation task on all metrics, and they showed larger inter-individual variability. They made longer fixations with greater dispersion amplitudes and fewer fixations in total. Fixations were further apart in both time and space, linked to jumping between PRLs depending on gaze direction.
Conclusions :
Visual search degrades with age, in association with attention, processing speed, and memory decline. The deficits in search found in AMD patients are the result of visual system losses overlaid on the normal age-related loss caused by cognitive/attention decline.
This is a 2021 ARVO Annual Meeting abstract.