A 2-Year History of Diplopia, Optic Disc Edema, and Amaurosis

Aright-handedmanin his 50s with a medical history of hypertensionwas referred for optic disc edema in the right eye and double vision. Hewas initially seen locally for new-onset double vision in upgaze without other visual symptoms. The patient had a 3-prism diopter left hypertropia in upgaze with full motility and was incidentally found to have optic disc edema in the right eye. His best-corrected visual acuity was 20/15 OU. Automated visual fields were normal, and there was no relative afferent pupillary defect. Magnetic resonance imaging (MRI) revealed no apparent abnormalities (Figure 1A). During the subsequent 6 months, the patient experienced graying of vision on rightward gaze. Results of an evaluation againdemonstratednormalvisual acuityandvisual fields.Results of a localworkup were negative, including acetylcholine receptor antibody.The patient presented to our clinic 2 years after initial symptom onset with continued graying of vision on eccentric gaze. His best-corrected visual acuity on examination was 20/25 OD and 20/20 OS. Relative afferent pupillary defectwas noted in the right eye. Therewas prominent chronic-appearing optic disc edema in the right eye without abnormalities in the left eye (Figure 1B). Results of visual field testing showed superior greater than inferior peripheral field loss in the right eye and normal visual field in the left eye.