Spatiotemporal Dynamics of Binocular Interaction in Anisometropic Amblyopia Revealed by Classification Image

Purpose: To explore the spatiotemporal dynamics of binocular interaction in anisometropic amblyopia. Methods: Ten anisometropic amblyopes (26.2 ± 3.8 years) and 10 normal people (23.6 ± 2.0 years) participated in this study. The noise stimulus was a sequence of 9 frames, each consisting of 11 vertical, spatially adjacent bars whose luminance were randomly sampled. The participants detected whether a brighter bar (target) appeared in the noise stream under two monocular and two dichoptic conditions. The spatiotemporal perceptive field (PF) in each condition was obtained with subsecond and subdegree precision using a classification image technique. The spatiotemporal dynamics of modulation from one eye to the other eye was determined by subtracting the other eye's monocular PF from the eye's dichoptic PF. Results: Monocular PFs in both fellow eyes (FE) and amblyopic eyes (AE) peaked earlier temporally and showed coarser spatial resolution in AE compared with normal eyes. In the normal group, the interocular modulations were similar in the two eyes and exhibited a facilitative region at target location and inhibitive region before the target's onset. In the amblyopic group, the interocular modulations were spatiotemporally different, with a diminished effect of AE on FE and a strengthened effect of FE on AE. Conclusions: The dynamics of reciprocal interactions between AE and FE differed not only in the magnitude, but also in the entire spatiotemporal profile. Our study provides valuable insights into the dynamics of the binocular visual processing and new constraints for theoretical modelling for binocular vision.