Background: Multiple studies on recovery of hemianopsia after cerebrovascular accident report visual-field enlargements after stimulation of the visual-field border area. These enlargements are made evident by the difference between pre- and post-training measurements of the visual field. Until now, it was not known how the visual-field enlargement develops.
Aim: To study how the enlargement develops as a function of time.
Methods: 11 subjects were trained by stimulating the border area of their visual-field defect using a Goldmann perimeter. The visual-field border location was assessed using dynamic Goldmann perimetry before, after and during training (after each 10th training session). To monitor eye fixation, a video-based eye-tracker was used during each complete perimetry session.
Results: It was found that visual-field enlargement during training is actually a gradual shift of the visual-field border, which was independent of the type of stimulus-set used during training. The shift could be observed while eye fixation was accurate.
Conclusion: Visual-detection training leads to a decrease in detection thresholds in the affected visual-field areas and to visual-field enlargement. Training effects can be generalised to important daily-life activities like reading.
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Funding This study was subsidised by the following Dutch foundations: Stichting centraal fonds RVVZ (proj. doss. 795); Stichting NUTS-OHRA (proj. SNO-T-08-30); Stichting Blindenpenning.
Competing interests None.
Ethics approval The study was approved by the medical ethics committee METC, Utrecht, The Netherlands under protocol number 98/271.
Patient consent Obtained.
Provenance and Peer review Not commissioned; externally peer reviewed.