What is the function of the optic nerve?

The optic nerve plays a crucial role in vision by transporting neural impulses generated by the retina directly to the brain. When light enters the eye, it is focused onto the retina where specialized photoreceptor cells convert this light into electrical signals. These signals need to be sent to the brain for interpretation, and that is where the optic nerve comes in. It acts as the communication pathway, ensuring that visual information reaches the brain, where it is processed, allowing us to understand what we see.

The other functions described in the other choices do not pertain to the optic nerve's role. Focusing light on the retina is primarily the job of the lens and cornea, controlling pupil size is managed by the muscles around the iris, and refracting light is mainly done by the cornea and lens. Thus, the primary function of the optic nerve is to carry the visual information from the eye to the brain, making it integral to the process of vision.