Episodic monocular constriction of the visual field sparing central vision occurred repeatedly, involved either eye, and lasted several minutes in a man with fatal periarteritis nodosa. Histologic study of the orbital and ocular vasculature showed inflammatory involvement of the arterial supply to the choroid. The highly distinctive transient ischemic attacks were attributed to intermittent choroidal vascular insufficiency. The preservation of central vision was attributed to features of the choroidal vascular supply that favor macular function.
Newman NM, Hoyt WF, Spencer WH. Macula-Sparing Monocular BlackoutsClinical and Pathologic Investigations of Intermittent Choroidal Vascular Insufficiency in a Case of Periarteritis Nodosa. Arch Ophthalmol. 1974;91(5):367-370. doi:10.1001/archopht.1974.03900060379006