Question

Why is it important for the optic nerve to be connected to the retina?

Answer 1

Optic nerves basically link our eyes with the brain.
The images which we see are first perceived by the retina as impulses.

For example if we are seeing many trees and flowers , our retina first perceives the qualities of these plants like the color, the intensity and creates impulses.

These impulses are sent via our optic nerves to the brain.

So in order to be able to see the final image as it is, the brain needs to be able to interpret these impulses which can only happen if optic nerves transmit these impulses to the brain in the first place.