Giant cell arteritis can cause sudden vision loss mainly due to occlusion of which artery?

• A. Central retinal artery
• B. Internal carotid artery
• C. External carotid artery
• D. Ophthalmic artery

Answer: (D)

Giant cell arteritis causes sudden vision loss mainly through ischemia of the optic nerve head due to inflammation and occlusion of the short posterior ciliary arteries, which are branches of the ophthalmic artery. The ophthalmic artery supplies the vessels feeding the optic nerve head, so its compromise directly leads to acute ischemic optic neuropathy and rapid vision loss. Upstream occlusion of the internal carotid would cause broader cerebral effects, the external carotid doesn’t supply the intraocular structures, and while central retinal artery occlusion can cause vision loss, the typical GCA mechanism targets the posterior ciliary/optic nerve circulation via the ophthalmic artery.