Arteritic anterior ischemic optic neuropathy with positive myeloperoxidase antineutrophil cytoplasmic antibody

Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is related to smallvessel vasculitis. There have been some reports of optic nerve involvements with increased values of MPO-ANCA. We report two cases of anterior ischemic optic neuropathy (AION) in which ANCA-associated vasculitis was suspected to be responsible for the pathogenesis. A 66-year-old man and a 72-year-old man had ocular symptoms of AION in both eyes with positive MPO-ANCA. Both patients showed high erythrocyte sedimentation rate, C-reactive protein, and MPOANCA values at first. Temporal artery biopsies were negative for temporal arteritis, whereas small-vessel vasculitis was found only in the latter patient. Visual dysfunctions remained unchanged after steroid pulse therapy, although laboratory data returned to normal levels after the treatment. Fluorescein angiography revealed selective occlusion of capillaries, arterioles, and precapillaries in the retina and choroid as well as in the optic disc. The identical characteristics of the angiographic findings of both eyes in the two cases indicated that the obliteration of small vessels in the intraocular arterial system was closely related to MPO-ANCA-associated vasculitis.