Following stroke, loss of one half of the visual field in both eyes (hemianopia) occurs in about 50% of stroke survivors. A stroke in the left side of the brain can cause a loss of vision in the inside of the left eye (the part nearest the nose), and outside of the right eye (the part furthest from the nose). This means the person cannot see anything in the right hand side of their normal field of view. The extent of the loss of vision can vary between patients, with some patients losing half of their field of view, while other patients lose less.
Two common treatments to improve the vision of patients with hemianopia are training in visual scanning techniques and the use of prisms. Visual scanning involves training the individual to make more effective eye movements into the side of their visual loss to compensate better for their blind side. Prisms are used to move images of objects in the blind side of vision into the seeing part of vision, which is a cue for the individual to look towards their blind side.
The aim of this work is to determine whether using either/or both of these treatments offers a better outcome than the current “information only” standard care. If the treatment options are successful then it is possible that this could be a new method of standard care.