Visual fields test the peripheral vision of the patient. Many disease processes affect the visual fields because they either damage the optic nerves or the brain where vision is processed. Because it is difficult to directly examine these structures, visual fields provide a careful way to evaluate their function instead.
Because visual fields can detect subtle changes in a disease process, they are very helpful for many patients in order to check on the progress of their disease. Glaucoma, optic neuritis, strokes, high intracranial pressure are just a few of the diseases that are followed by repeated visual fields.