The ophthalmic artery (a branch of the internal carotid) supplies the eye, orbit, and accessory structures. It gives rise to key branches, including the central retinal, ciliary, ethmoidal, and supraorbital arteries. Venous drainage occurs through the superior and inferior ophthalmic veins, which connect to the cavernous sinus. Clinical conditions include retinal artery occlusion, cavernous sinus thrombosis, and glaucoma-related venous congestion.