Night blindness is associated with deficiency of which vitamin?

• A. A
• B. C
• C. niacin
• D. thiamine

Answer: (A)

Night vision in dim light relies on rhodopsin in the rod cells of the retina, which requires a vitamin A–derived component (11-cis-retinal) to form and regenerate. When vitamin A is deficient, rhodopsin cannot be produced efficiently, and the eyes struggle to adapt to low light, producing night blindness. This makes night blindness a classic sign of vitamin A deficiency, which can be followed by more serious eye problems like Bitot’s spots and corneal damage if the deficiency continues.

The other nutrients listed are not primarily linked to this symptom: vitamin C deficiency leads to scurvy with gum and skin problems; niacin deficiency causes pellagra (diarrhea, dermatitis, dementia); thiamine deficiency causes beriberi or Wernicke–Korsakoff syndrome. So vitamin A deficiency best explains night blindness.