Abstract
Deficits in global motion and global form perception have been reported in amblyopia. We examined how such deficits manifest in the visual function thought to be reliant on the interactions between these two processing mechanisms using the implied motion stimulus. A total of 13 amblyopes (8 strabismic and 5 anisometropic) and 6 visually normal controls monocularly discriminated the overall implied motion in dynamic Glass pattern (dGlass) in the presence of varying external noise. The results showed higher thresholds for strabismic (no noise, amblyopic = 3.61°±1.50, fellow = 3.15±2.02) compared to anisometropic (no noise, amblyopic = 2.17°±1.34, fellow = 2.43±1.72) and normal (no noise = 2.23°±1.26) participants. The nested models were tested to estimate the relative contribution of internal noise and sampling efficiency parameters to explain the threshold change across different groups. The results showed no difference in performance for amblyopes compared to the normal controls (p's > 0.05). The thresholds for implied motion were then compared to global form (static Glass pattern; sGlass) and global motion (RDK). The nested models from all three stimuli were statistically compared to investigate how global motion and global form thresholds are different from the implied motion thresholds. The results showed no difference between thresholds for dGlass and RDK but higher thresholds for sGlass pattern best described the data, implying that the additional signal in dGlass might have improved amplyopic performance. Our result challenges the dorsal stream dysfunction hypothesis where motion processing is assumed to be more impaired than form processing in amblyopia.
Meeting abstract presented at VSS 2018