LAUSR

O ptic disc edema, a potential complication of acute retinal necrosis (ARN), usually develops concurrently or after the development of retinal abnormalities. In the few reported cases of ARN with optic disc edema, retinal involvement and uveitis were evident as well. We describe a patient with ARN initially presenting with only optic disc edema and with no other signs of ARN, mimicking nonarteritic anterior ischemic optic neuropathy (NAION). A 59-year-old woman reported a 3-day history of painless blurred vision in her left eye. Her general health was excellent, and she was taking no medications. Visual acuity was 20/20 in both eyes, and there was a left relative afferent pupillary defect. Color vision was intact. Slit-lamp examination was normal. The right fundus appeared normal. The left fundus also was unremarkable, except for left optic disc edema (Fig. 1). Automated visual field testing was normal in the right eye and showed a superior arcuate defect in the left eye. Orbital MRI was normal. A presumptive diagnosis of NAION was made, and prednisolone (40 mg) with low-dose aspirin was prescribed. Ten days later, the patient had marked decreased vision in both eyes, with acuity of 20/2,000, right eye, and 20/800, left eye. The anterior chamber showed trace cells in the right eye and 2+ cells in the left eye. Fundus examination demonstrated optic disc edema in the right eye and advanced optic disc swelling and peripheral retinal necrosis in the left eye (Fig. 2). The right retina had no peripheral abnormalities, which was confirmed on