Nyctalopia or night blindness is not a disease itself, but it usually indicates another eye condition. Some types of nyctalopia are treatable; others are not. People with night blindness aren’t necessarily unable to see at night, but they experience poorer vision in low light. The problem becomes worse after moving from a brightly lit environment to a darker one. Nyctalopia may be present from birth, but disease, vitamin deficiencies, age, and injury can cause or contribute to the symptom.
Most people with nyctalopia find their vision decreases in low light. The retina detects light and color. The photoreceptor cells in the retinas, the rods, sense the amount of light entering the eye. Some eye diseases, as well as the natural aging process, cause degeneration of the rods and prevent a person’s vision from adjusting to low light. Other causes are genetic. The ability to detect light depends on the amount of Rhodopsin, a protein also called visual purple, in the retina. Some individuals inherit a Rhodopsin deficiency, which doctors can diagnose at birth. It often results from a vitamin deficiency.
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