The discovery also uncovers a new mechanism for how vision degrades, which could lead to a new class of drugs to reverse it.Age-related macular degeneration (AMD) is one of the most common causes of blindness in older people, characterized by vision that degrades slowly in the center of the visual field. Retinitis pigmentosa (RP) is a rare genetic disorder that similarly affects the peripheral vision. In both cases, vision can't be restored once it's lost, but progression of symptoms can be slowed down.