The Oculus Easy Field visual fields instrument checks the health and function of the visual pathways from the eyes back to the brain, as well as the vision portion of the brain. The instrument looks for small areas of missing vision in your visual world. These are not noticed at early stages by people because their vision in their right and left eyes overlap. Diseases that manifest losses of visual fields includes glaucoma, multiple sclerosis, stroke and pituitary tumors as well as many others. Subtle losses of visual fields may be the first sign of disease.
For more information follow this link: http://www.oculus.de/en/sites/detail_ger.php?page=295