Question

Deficiency of which vitamin causes night blindness?

• A. Vitamin A
• B. Vitamin B
• C. Vitamin C
• D. Vitamin D

Hint:

Night blindness happens when the retina cannot make enough of the light sensitive pigment that needs a specific vitamin.

Answer 1

The Correct Option is A

Step 1: Recall the role of Vitamin A in vision.
Vitamin A is needed to make a pigment called rhodopsin, found in the rod cells of the retina. Rod cells are responsible for vision in dim light, so rhodopsin is essential for seeing properly at night or in low light conditions.

Step 2: Link deficiency to the disease.
When the body does not get enough Vitamin A, the retina cannot make sufficient rhodopsin. This makes it hard for the eyes to adjust to darkness, a condition known as night blindness or nyctalopia. Long term deficiency can also cause dryness of the eye and, in severe cases, permanent damage to the cornea.

Step 3: Rule out the other vitamins.
Vitamin B deficiency mainly causes nerve problems, skin issues and anaemia, not night blindness. Vitamin C deficiency causes scurvy, marked by bleeding gums and weak connective tissue. Vitamin D deficiency affects bone health, causing rickets in children and osteomalacia in adults, and is not linked to night vision.

Final Answer:
Deficiency of Vitamin A causes night blindness. \[ \boxed{\text{Vitamin A}} \]