Perimetric evaluation of saccadic latency, saccadic accuracy, and visual threshold for peripheral visual stimuli in young compared with older adults.

PURPOSE

Using a novel automated perimetry technique, we tested the hypothesis that older adults will have increased latency and decreased accuracy of saccades, as well as higher visual thresholds, to peripheral visual stimuli when compared with younger adults.

METHODS

We tested 20 healthy subjects aged 18 to 30 years ("young") and 21 healthy subjects at least 60 years old ("older") for detection of briefly flashed peripheral stimuli of differing sizes in eight locations along the horizontal meridian (±4°, ±12°, ±20°, and ±28°). With the left eye occluded, subjects were instructed to look quickly toward any seen stimuli. Right eye movements were recorded with an EyeLink 1000 infrared camera system. Limiting our analysis to the four stimulus positions in the nasal hemifield (-4°, -12°, -20°, and -28°), we evaluated for group-level differences in saccadic latency, accuracy, and visual threshold at each stimulus location.

RESULTS

Saccadic latency increased as stimulus size decreased in both groups. Older subjects had significantly increased saccadic latencies (at all locations; P < 0.05), decreased accuracies (at all locations; P < 0.05), and higher visual thresholds (at the -12°, -20°, and -28° locations; P < 0.05). Additionally, there were significant relationships between visual threshold and latency, visual threshold and accuracy, and latency and accuracy (P < 0.0001).

CONCLUSIONS

Older adults have increased latency and decreased accuracy of saccades, as well as higher visual thresholds, to peripheral visual stimuli when compared with younger adults. Saccadic latency and accuracy are related to visual threshold, suggesting that saccadic latency and accuracy could be useful as perimetric outcome measures.