Selective loss of vergence control secondary to bilateral paramedian thalamic infarction.

The supranuclear pathways for vergence eye movements are poorly understood. The authors report a 57-year-old patient who presented with selective loss of vergence control and dissociation of light and near reaction. MRI showed a symmetric paramedian thalamic infarction without midbrain lesion. The findings suggest that this syndrome is due to an interruption of supranuclear fibers to midbrain vergence neurons.