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Why is vitamin A important for vision?

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structural formulas of some organic compounds — organic compound The structures of organic compounds can be depicted in condensed, expanded, and three-dimensional structural formulas.

Vitamin A is essential for vision because it is a key component of rhodopsin, a light-sensitive pigment found in the retina of the eye.1

Specifically, the body converts vitamin A into 11-cis-retinaldehyde, which combines with a protein called opsin to form rhodopsin. This pigment is located in the rod cells of the retina and is responsible for enabling vision in dim light. When light strikes the eye, it triggers a chemical change in the rhodopsin molecule, initiating a signal that is transmitted to the brain.23

Because rhodopsin requires a constant supply of vitamin A to maintain its photosensitivity and to regenerate after exposure to light, a deficiency in this compound leads to night blindness—a reduced ability to adapt to darkness. If the deficiency persists, it can lead to more severe ocular damage, including xerophthalmia, which may result in permanent blindness.21