An occult case of giant cell arteritis presenting with combined anterior ischemic optic neuropathy and cilioretinal artery occlusion.

A 61-year-old female presented with a moderate decrease in vision in the left eye. The patient denied any other ocular or systemic symptoms related to giant cell arteritis. Visual acuity was 20/50 in the left eye with a 2+ relative afferent pupillary defect and markedly abnormal color vision. Dilated fundus examination and flourescein angiography revealed optic disc edema as well as a cilioretinal artery occlusion. Erythrocyte sedimentation rate was only slightly elevated. Subsequent biopsy of the superficial temporal artery confirmed the diagnosis of giant cell arteritis. Cilioretinal arteries are anatomical variants derived from the short posterior ciliary arteries. Arteritic anterior ischemic optic neuropathy typically results from thrombotic occlusion of the short posterior ciliary arteries. Consequently, arteritic occlusion of the short posterior ciliary arteries can result in concomitant occlusion of the cilioretinal artery. This case highlights the situation where clinical symptoms were not suspicious for giant cell arteritis but the presence of an anterior ischemic optic neuropathy and a cilioretinal artery occlusion was virtually pathognomonic for giant cell arteritis.