Which vitamin is primarily responsible for maintaining healthy vision?

Vitamin A is the vitamin primarily responsible for maintaining healthy vision due to its essential role in the formation of visual pigments in the retina. It is a critical component of rhodopsin, a protein in the eye that allows us to see in low light conditions. Adequate levels of vitamin A contribute to proper functioning of the retina and overall eye health, helping to prevent conditions such as night blindness and supporting overall vision clarity.

The other vitamins listed, while important for various bodily functions, do not have the same direct impact on vision as vitamin A. Vitamin E is primarily an antioxidant, supporting immune function and skin health; vitamin D plays a key role in bone health and calcium metabolism; and vitamin K is vital for blood clotting and maintaining bone density. However, none of these vitamins directly contributes to the maintenance of healthy vision in the way that vitamin A does.