Question

Night blindness is caused due to deficiency of
(A) Vitamin - C
(B) Vitamin - A
(C) Vitamin - D
(D) Vitamin - E

Answer 1

Hint: Night blindness is the disease caused due to deficiency of vitamin which is a group of unsaturated nutritional organic compounds that includes retinol, retinal, and several provitamins. This vitamin is also known as retinol.

Complete answer:
Night blindness is caused due to deficiency of Vitamin – A. The retina of the eye requires vitamin -A, which is used in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light and color vision.

Additional Information: Vitamin A is only found in animal-sourced foods, such as oily fish, liver, cheese, and butter. Our body can produce vitamin A from carotenoids found in plants.

Night-blindness is defined as a condition making it difficult or impossible to visualize in relatively low light. It's an indication of several eye diseases. The nyctalopia may exist from the birth of the child, or be caused by injury or malnutrition. It may be described as an insufficient adaptation to darkness. The most common reason for nyctalopia is retinitis pigmentosa, a disorder during which the rod cells within the retina gradually lose their ability to respond to the light. Patients affected by this genetic condition have progressive nyctalopia and eventually, their daytime vision can also be affected. In X-linked congenital stationary nyctalopia, from birth, the rods either don't work on all, or work little or no, but the condition doesn't intensify.
So, the correct answer is ‘(B) Vitamin - A’.

Note: It was found that Night blindness is also caused due to Deficiency of rhodopsin in rods. The pigment rhodopsin is found to be extremely sensitive to light, and thus it helps to improve vision in low-light conditions.