Patterns of spatial distortions in human amblyopia are invariant to stimulus duration and instruction modality

We investigated the patterns of two-dimensional spatial distortions in human amblyopia, using three different psychophysical mapping procedures. Strabismic and strabismic-anisometropic amblyopes showed consistent distortions, consisting in enlargement, shrinkage, or torsion of portions of the tested visual field. Purely anisometropic amblyopes and strabismics with alternating fixation showed increased spatial uncertainty, but no consistent distortions. For all groups of subjects, there was a very good correspondence between the patterns of distortion obtained with the three methods. We conclude that the spatial distortions are robust across different procedures. They might reflect a genuine rearrangement of the cortical topography as a result of strabismus.