Community-Based Trial of a Peripheral Prism Visual Field Expansion Device for Hemianopia

Abstract
Homonymous visual field defects (HVFDs) have a prevalence of 0.8% in the general population older than 49 years.1 They are caused by lesions in the postchiasmal visual pathways, primarily due to strokes and, to a lesser extent, trauma and tumors.2 Patients with HVFDs have difficulty detecting obstacles on the side of the loss, resulting in impaired mobility. The main vision-based rehabilitation strategies include provision of optical aids (eg, prismatic corrections to expand or relocate the visual field)3; visual search training to improve the efficiency of visual exploration on the side of the loss4-7; and visual restoration training to recover lost visual function.8 Herein we report, to our knowledge, the first multicenter evaluation of a novel prismatic device to expand visual fields for patients with HVFDs.