Question

(a) What is 'blind spot' in the eye?

(b) What is night blindness? What causes night blindness?

Answer 1

(a) Blind spots in our vision are called “scotomas”. It is the small circular area at the back of the retina where the optic nerve enters the eyeball and which is devoid of rods and cones and is not sensitive to light. For example, when you are driving a car, the area just behind your shoulders is often a blind spot.
(b) Light blindness is a symptom of several eye diseases. Night blindness may exist from birth, or by injury or malnutrition (for example, vitamin A deficiency). The most common cause of nyctalopia is retinitis pigmentosa, a disorder in which the rod cells in the retina gradually lose their ability to respond to the light.