Abstract
Purpose :
Smooth pursuit is known to be impacted in macular degeneration. In this study we test whether this loss of function can be modulated by the demands of the task (Shanidze et al, 2016). We hypothesize that smooth pursuit will be impacted when the task is more demanding and requires the pursuit of an acuity-limited target. Here we tested this hypothesis in individuals with macular degeneration (MD) and age-matched controls.
Methods :
6 participants (4 MD, 2 Controls) were tested in the confocal scanning laser ophthalmoscope (SLO-101, Rodenstock, Munich, Germany), which allows for direct target visualization on the retina. Subjects were asked to acquire and track a target for the entirety of the trial. The target was an annulus that changed briefly to a Landolt C of the same diameter and moved horizontally to the left or the right in a step-ramp manner (Rashbass, 1961), at 5o/s. The Landolt C had one of 4 possible orientations and appeared for 300 ms at 4 different time points in the trial. Subjects were asked to identify the orientation of the Landolt C. Target size was adjusted to achieve an accuracy of 75% during static presentation, and ranged from 0.5o to 5.3o.
Results :
For MD participants, pursuit gains were significantly lower (p < 0.01, paired sample t-test, Figure 1) during Landolt C presentation, compared to annulus presentation. For controls, gains were similar during Landolt C and annulus presentation, and comparable to gain for MD participants during annulus presentation. For 7 out of 8 MD eyes, there was a strong correlation between accuracy and gain (R2=0.71, p=0.017), suggesting that during demanding tasks both accuracy and gain are impaired in MD.
Conclusions :
Our results indicate that smooth pursuit gain is task-dependent and is impacted when the task is acuity limited, particularly for participants with macular degeneration.
This is a 2020 ARVO Annual Meeting abstract.