Glossary
					Blind-sight: 
					The ability to respond to certain visual stimuli within a 
					perceptually blind area of visual field. 
					Homonymous hemianopia: 
					Loss of half of the field of vision to one side in each eye.
					Monocular vision: 
					vision in one eye only.
					Peripheral vision: 
					field of vision out to both sides.
					Prism: 
					Optical plastic membrane which displaces images which are 
					viewed through the prism.
					Quadrantanopia: 
					Loss of a quarter of the field of vision.
					Scotoma: 
					isolated area of visual field loss.
					Visual field: the whole of vision from straight ahead to 
					the periphery (outwards).
					Visual impairment: vision loss resulting in a limitation 
					of visual capability.
					Visual scanning: training that encourages an individual 
					to systematically look to the right and left sides.