Night blindness is a symptom of deficiency in which vitamin?

Night blindness is a symptom of deficiency in which vitamin?

• A. Vitamin D deficiency
• B. Iron deficiency
• C. Vitamin A deficiency
• D. Magnesium deficiency

Answer: (C)

Night vision depends on a pigment in the retina called rhodopsin, which requires retinal, a form of vitamin A, to function. When vitamin A intake is low, retinal production falls, rhodopsin regeneration slows, and the eyes struggle to adapt to low light, causing night blindness. If deficiency continues, the ocular surface can dry and other eye problems can develop. Vitamin D deficiency mainly affects bones and mineral balance; iron deficiency leads to anemia and fatigue; magnesium deficiency disrupts numerous enzyme and nerve functions. None of these are directly tied to the ability to see in dim light, so vitamin A deficiency is the best explanation for night blindness.

Night vision depends on a pigment in the retina called rhodopsin, which requires retinal, a form of vitamin A, to function. When vitamin A intake is low, retinal production falls, rhodopsin regeneration slows, and the eyes struggle to adapt to low light, causing night blindness. If deficiency continues, the ocular surface can dry and other eye problems can develop.

Vitamin D deficiency mainly affects bones and mineral balance; iron deficiency leads to anemia and fatigue; magnesium deficiency disrupts numerous enzyme and nerve functions. None of these are directly tied to the ability to see in dim light, so vitamin A deficiency is the best explanation for night blindness.