Properties of the regained visual field after visual detection training of hemianopsia patients.

PURPOSE

To study the quality of the visual field areas that were regained after training. In those areas, we measured some of the elementary visual properties that make up the quality of visual functioning in daily-life. This was to provide information about whether the functional visual field had been enlarged.

METHODS

Patients with visual field defects after a CVA were trained to detect stimuli presented in the border area of the visual field defect. Then, in the regained areas, we measured visual acuity as a measure for spatial properties. Secondly, to assess for temporal properties we measured critical flicker frequency (CFF). Finally, we studied color vision as a third property of the regained areas.

RESULTS

Since we could not predict where restoration of visual fields would occur, we did not present pre-post comparisons. However, despite the fact that training was carried out with simple white light stimuli, we could assess acuity, CFF and color vision in the regained areas. The performance of the patients during testing of the elementary properties appeared to be almost normal when compared to control subjects and comparable to the patient's own ipsilesional visual field.

CONCLUSIONS

These results support the idea that the regained visual fields that emerged after training are actually used for processing additional visual stimuli other than those used during training.