It has three major branches which provide sensory innervation to the eye, and the skin of the upper face and anterior scalp, as well as other structures of the head.

[2] Within the skull, the ophthalmic nerve produces:[1] The ophthalmic nerve divides into three major branches which pass through the superior orbital fissure:[1] The ophthalmic nerve provides sensory innervation to the cornea, ciliary body, and iris; to the lacrimal gland and conjunctiva; to the part of the mucous membrane of the nasal cavity; and to the skin of the eyelids, eyebrow, forehead and nose.

It carries sensory branches from the eyes, conjunctiva, lacrimal gland, nasal cavity, frontal sinus, ethmoidal cells, falx cerebri, dura mater in the anterior cranial fossa, superior parts of the tentorium cerebelli, upper eyelid, dorsum of the nose, and anterior part of the scalp.

Roughly speaking, the ophthalmic nerve supplies general somatic afferents to the upper face, head, and eye: In comparison, the maxillary nerve (CN V2) provides general somatic afferents to the mid-face and mid-head.

[3] This article incorporates text in the public domain from page 887 of the 20th edition of Gray's Anatomy (1918)