Abstract
Purpose :
Central vision loss(CVL) adversely impacts a variety of visual functions and tasks, due to eye movement control and sensory differences in peripheral visual field. The impact of simulated CVL on pursuit eye movement control (accuracy, gain and corrective saccades) and visual function is not well known. We examine the effect of CVL on smooth pursuit and explore the impact of feedback designed to assist in the use of a preferred retinal locus(PRL).
Methods :
CVL was simulated with a 4°,7° or 10° diameter, mean luminance, gaze-contingent-scotoma with a Eyelink 2000Hz eyetracker on a 144Hz display at 60cm distance. 24(8 per diameter) normally-sighted participants (mean age 19.5years) were instructed to continuously look above a 4° moving target, simulating an inferior PRL.The target dot continuously moved on a circular path in clockwise or counterclockwise direction at 2.6°/s and periodically was replaced for 0.5s with a moving Gabor(𝝈=1°) tilted ±45°, then the direction of target was randomized.Gabor’s spatial frequency and contrast were controlled by a QuestPlus algorithm to measure contrast sensitivity function (CSF). Subjects indicated the orientation of grating.The role of feedback was explored using i)a scotoma awareness condition where the extent of the CVL was revealed using a black gaze-continent disk designed to mitigate against filling in; ii)a gaze-contingent ring whose size dynamically provided feedback concerning PRL placement. Repeated measures ANOVA was used to compare between and within subjects effects with Bonferroni correction for multiple comparisons.
Results :
Scotoma radius had a significant effect on the area under the CSF(AUCSF) (F=9.019,p=0.001) and CSF acuity (F=5.875,p=0.009). Scotoma awareness had a significant effect on smooth pursuit gain(F=6.145,p=0.022), AUCSF(F=9.735,p=0.005), and CSF acuity(F=9.122,p=0.007). Gaze contingent feedback had no overall effect on any parameters, except at the largest scotoma size where vertical accuracy was better with the feedback on(mean difference=1.630,p=0.014).There was no interaction between feedback and scotoma awareness and also no three way interaction.
Conclusions :
These results show that oculomotor and sensory behavior are adversely affected by CVL during smooth pursuit and suggest that scotoma awareness visual feedback may improve eye movement control and visual performance, especially for those with larger central scotomas.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.