Here is a video posted on YouTube by Chadwick Optical, makers of prisms stuck onto glasses to treat hemianopia. These prisms bring part of the blind visual field into the seeing field. They were developed by Eli Peli, Professor of Ophthalmology at Harvard Medical School. He describes how it works in this paper. Like most hemianopia rehabilitation strategies this method has not been clearly proven in a clinical trial, but there is some supporting scientific evidence.
There are a couple more videos on Chadwick Optical's YouTube channel here.