Induced visual sensitivity changes in chronic hemianopia

Purpose of review

Postgeniculate lesions commonly result in visual field loss. These areas of blindness at the chronic stage were thought to be permanent and irreversible. Recent evidence demonstrating changes in visual sensitivity within the field defect following training is reviewed.

Recent findings

It was previously demonstrated in animal models that visual deficits following brain injury are transient and less severe than those found in human patients. Previous attempts at visual rehabilitation, prompted by findings in the animal models, were successful in helping hemianopic patients to develop coping strategies. Nevertheless, these were criticized because some of the findings could be accounted for by imprecise or uncontrolled eye movements. More encouraging is recent research showing that repeated stimulation of the field defect, using a wide range of visual targets, may lead to increased visual sensitivity within the blind field. These findings are in accordance with our current understanding of visual pathways.

Summary

Recent rehabilitation interventions, should they be proven effective in large-scale clinical trials using appropriate controls, could lead to an overhaul of the current therapeutic management of this condition.