NAION is the most common cause of acute optic nerve disease in the elderly, causing permanent and severe visual loss. No proven treatment currently exists to reverse or arrest this loss. There is no accepted method for the prevention or reduction of the likelihood of second eye involvement. NAION strikes both eyes in as many as 40 percent of affected patients (Beri et al. 1987), with a 2-year risk of about 25 percent (Steven Feldon, personal communication to SEK).