Effects of external noise on motion perception in amblyopia

There are two conflicting opinions about the mechanism of the motion perception deficit in amblyopia. One is that the deficit observed in temporal detection test ought to be accounted for by the deficit of the visual spatial information input from the amblyopic eye, while the other focuses on the temporal detection deficit of amblyopes. So far, no systematic research with external noise has been performed on the temporal perception of visual stimuli in amblyopia. In this study, we used drifting vertical sine-wave gratings under different temporal frequencies as stimuli, and compared the motion direction discrimination performances between fifteen anisometropic amblyopes and nineteen normal controls in the conditions with and without external noise. It can be concluded that the contrast sensitivity ratios between amblyopic eyes and non-amblyopic eyes are independent on the temporal frequency, and the external noise has the equivalent impact on the temporal detection performance in amblyopes and normal controls. Thus, it reveals that the temporal perception pathway of amblyopes is intact. This study can help with understanding the impairment mechanisms of amblyopia and pursuing a suitable therapy for amblyopes.