Question

Why does optic nerve cause a blind spot?

Answer 1

Optic nerves basically link our eyes with the brain.
This nerve extends from the retina of our eyes till our brain.

Now, the beginning of the optic nerve which originates from the retina is called optic disc and it lacks photoreceptors (cones and rods) and hence does not get stimulated on receiving light, as a result it is referred to as the blind spot.