The ophthalmic nerve, also known as the first cranial nerve or CN I, is a sensory nerve that transmits visual and non-visual information from the eye and parts of the face to the brain. It carries afferent fibers for the senses of sight, smell, and touch. The ophthalmic nerve has three major branches: the nasociliary nerve, the frontal nerve, and the lacrimal nerve. These nerves provide sensory innervation to the forehead, eyelids, conjunctiva, cornea, and mucous membranes of the nose. Any damage to the ophthalmic nerve can result in vision loss or other sensory impairments in these areas.