Rehabilitation training of homonymous visual field defects in patients with postgeniculate damage of the visual system.

Training-dependent improvement of visual behavior after postgeniculate damage of the visual system was studied in 10 patients. The patients, all with computer-tomographically proven damage and a lesion chronicity of 8 weeks to 4.7 years, were subjected to a special exploration training of at least 10 sessions or 1100 trials. Before and after training, extensive perimetric tests were performed to determine possible training-related visual changes. It was found that the training program improved visual exploration considerably and induced qualitative shifts in exploration strategy even for patients who had failed to adopt these strategies for more than 3 years postlesion. On the other hand, a training-based visual field enlargement was not supported when applying strict criteria. It is concluded that specific and systematic exploration training can be of significant help for improving visuo-spatial behavior in hemianopic patients, but that a reliable visual field enlargement is unlikely to occur in unselected patients trained and examined under standard conditions.