Night blindness is a condition characterized by difficulty seeing in dim light or at night. It is caused by a deficiency of certain nutrients, specifically vitamin A. Vitamin A is essential for the proper functioning of the retina, the part of the eye responsible for detecting light. When there is a deficiency of vitamin A, the retina is unable to produce a pigment called rhodopsin, which is important for low-light vision. Without enough rhodopsin, the eyes struggle to adjust to low levels of light, resulting in night blindness. Vitamin A deficiency can occur due to a lack of dietary intake or poor absorption of the vitamin. Thus, it is important to consume foods rich in vitamin A, such as carrots, spinach, and sweet potatoes, to maintain good eye health and prevent night blindness.