Purpose:
We aim to use a new automated perimetry technique to test the hypothesis that adults sixty years of age and older will have higher visual thresholds along with an increased latency and decreased accuracy of eye movements when compared to younger adults.
Methods:
We tested 20 subjects aged 18-30 years old ("younger"), and 21 subjects at least 60 years old ("older") for detection of stimuli in 8 locations along the horizontal meridian (4 left, 4 right). Eye movements (monocular, right eye) were recorded with an EyeLink1000 infrared camera. System accuracy measuring the horizontal visual field was <0.5°, with temporal resolution of 1000 Hz. Limiting our analysis to the 4 stimulus positions in the left visual field, we used repeated-measures ANOVA on ranks to evaluate group-level differences in saccadic eye movement latency, accuracy, visual threshold, and frequency of seeing curve data for each stimulus position.
Results:
Latency, accuracy, and visual threshold between groups at -4°, -12°, -20°, and -28° are shown in the figure. Older subjects had higher visual thresholds, decreased accuracy, and increased latency. Furthermore, latency increased as stimulus size approached visual threshold. Repeated-measures ANOVA on ranks showed statistically significant differences (P < 0.05) between the groups in threshold (-12°, -20°, -28°), latency (-4°, -12°, -20°, -28°), and accuracy (-4°, -12°, -20° and -28°).
Conclusions:
Eye movement perimetry showed significant differences in visual threshold, saccadic latency, and saccadic accuracy between younger and older groups for positions along the horizontal meridian. Further refinement of this technique will provide a tool permitting automated, whole-field perimetry testing along with novel, eye-movement based measures that reflect the health of the visual system.
Keywords: perimetry • visual fields • eye movements: recording techniques