What is the primary function of the optic nerve?

The primary function of the optic nerve is to connect the eye to the brain. This nerve transmits visual information from the retina, which is at the back of the eye, to the visual cortex in the brain, allowing us to perceive and interpret what we see. The optic nerve is critical in conveying signals that represent the images formed on the retina, making it essential for vision. Without this connection, the brain would not receive any visual input, rendering sight impossible.

Other options address different aspects of vision and ocular function, such as eye movement control, pupil size regulation, and visual information processing in the retina, but they do not capture the main role of the optic nerve in transmitting visual signals from the eye to the brain.