Total blindness occurs when a person cannot see anything, including light, and is caused by several conditions. Glaucoma causes damage to the optic nerve, which relays visual information to the brain. Cataracts are common in older people and can cause cloudy vision. Macular degeneration also affects the older population and destroys the macula, the part of the eye responsible for sharp central vision. Optic neuritis is inflammation that can lead to temporary or permanent vision loss. Loss of vision in optic neuritis can range from blurry vision to blind spots to total blindness. Diabetic retinopathy can cause blindness if left untreated. Although retinitis pigmentosa rarely leads to blindness, it can damage the retina.