The ophthalmic nerve is the smallest branch of the trigeminal nerve and is responsible for sensory innervation of the eye and surrounding tissues. There are a few synonyms for the ophthalmic nerve, including the first division of the trigeminal nerve, V1, and the nasociliary nerve. The V1 nerve is divided into three branches: the nasociliary nerve, which provides sensory innervation to the nose, forehead, and eye; the frontal nerve, which innervates the forehead and scalp; and the lacrimal nerve, which innervates the lacrimal gland and conjunctiva. The ophthalmic nerve is essential for the normal functioning of the eye and is responsible for sensing pressure, temperature, and pain.