A 35-year-old man was admitted as an inpatient for altered mental status and experienced acute-onset bilateral decreased vision on the second day of hospitalization. He denied any medication use and had no previous history of ocular surgery or known ophthalmic disorders.
On examination, visual acuity with correction was 20/400 OD and 20/100 OS. Intraocular pressure was within normal limits. Both pupils were briskly reactive without an afferent pupillary defect. Slitlamp examination was unremarkable. Dilated fundus examination of both eyes revealed peripapillary retinal whitening emanating from the optic nerve and encroaching into the macula, more pronounced in the right eye (Figure 1A). Late-phase frames of fluorescein angiogram in both eyes revealed hypofluorescence corresponding to the areas of retinal whitening and obscuring the choroidal fluorescence in these areas, along with nasal peripapillary hyperfluorescence in the areas of retinal whitening (Figure 1B).