Abstract
Purpose :
To investigate whether glaucomatous visual field loss produces measurable changes in eye movements.
Methods :
Fifteen glaucoma patients with asymmetric vision loss (>6dB difference in Humphrey Mean Deviation [MD] between eyes) were asked to view 120 images of natural scenes. Images were presented sequentially on a computer monitor, and were viewed monocularly once with each eye. Patient’s eye movements were recorded using the Eyelink 1000 eye-tracker. Eye-movement parameters were computed and compared within participants. These included a novel measure: saccadic reversal rate (SRR), as well more traditional eye movement metrics such as saccade amplitude, fixation counts, fixation duration, and the bivariate contour ellipse area (BCEA) of fixation locations. In addition, the relationship between these parameters and clinical measures of vision were investigated.
Results :
In the worse eye, average saccade amplitude and BCEA were smaller (P<0.05), while SRR was greater (P<0.05) compared to the better eye. There was a significant correlation between the inter-eye difference in BCEA, and differences in MD values (Spearman’s rho =0.65; P = 0.01), while differences in SRR were associated with differences in visual acuity (Spearman’s rho = 0.64; P = 0.01). Furthermore, between-eye differences in BCEA were a significant predictor of between eye difference in MD (R2 = 0.34, P = 0.01): for every 1 dB in MD difference between eyes the BCEA reduced on average by 6.2% (95% confidence interval of 1.6 – 10.3%).
Conclusions :
In glaucoma patients with asymmetric visual field loss, the eye with the worse visual field loss had restricted eye movements in spatial extent, and exhibited more frequent back-and-forth (“reversal”) saccades. Eye movements recorded during passively viewing images could potentially be used as biomarkers for worsening VF damage.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.