How is peripheral vision lost or diminished?
Peripheral vision can be lost because of glaucoma or a stroke. Although the loss caused by a stroke is sudden and obvious, the damage done by chronic glaucoma usually is gradual. Therefore, it is not apparent to the affected individual until considerable vision has been lost. Periodic tests of the visual field thus are important as people mature, because the incidence of glaucoma increases with age. Loss of peripheral vision is obvious to anyone with macular degeneration, a progressive condition in which deterioration of the macula, the central part of the retina, produces a growing blind spot in the center of the field of vision.
