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Definition of Night Blindness
Night Blindness – impaired dark adaptation resulting from slowed photochemical reactions in the rods, the specialized cells of the retina that perceive contrast and detect visual images in low light. Night blindness becomes increasingly common after middle age.
The person with night blindness may be unable to see at all in dim light or may experience delayed adjustment when going from a lighted environment to a dim or dark environment. A diminished visual field with restricted peripheral vision also contributes to night blindness, as the outer edge of the retina where peripheral vision takes place contains mostly rods.
There are not many treatment options for night blindness. Nutritional supplementation of vitamin A and the antioxidants lutein and zeaxanthin, which some studies show help maintain the health of the eye and improve the functioning of the rods, seem to aid some people.
Adequate lighting when reading and especially when watching television or movies reduces the need for the eye to make accommodations for changing light. Increased lighting can compensate for diminished dark adaptation in static settings such as rooms and offices, though it is not possible to make similar accommodations for functions such as driving.
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