What does the optic nerve primarily do?

The optic nerve primarily conducts impulses from the eyes' photoreceptors to the brain. This is essential for vision, as it transmits the visual information captured by the photoreceptors in the retina, which are specialized cells that respond to light. Once the photoreceptors convert light into electrical signals, the optic nerve carries these signals to the visual cortex in the brain, where they are processed and interpreted, allowing us to perceive images. This function is critical for the ability to see and understand our visual environment.

The other options relate to different functions: transmitting sound stimuli pertains to the auditory system, controlling eye movement is primarily managed by cranial nerves that innervate the extraocular muscles, and regulating light intake is a function controlled by the iris and pupil, not the optic nerve. This reinforces the specific role of the optic nerve in the visual processing pathway.