Mystery Case: Bilateral temporal crescent sparing after cardiac arrest.

A 48-year-old man complained of tunnel vision after he experienced a cardiac arrest with out-of-hospital resuscitation. Best-corrected visual acuities were 20/15 OD and OS. Pupil responses were unremarkable. Goldmann perimetry showed bilateral homonymous hemianopia with central sparing and presence of temporal crescents (figure 1). Funduscopic examination was normal OU. MRI demonstrated bilateral posterior watershed infarctions (figure 2). This particular visual field pattern with sparing of 2 visual field regions located on opposite anatomic poles in the visual cortex is rare1 and presumably results from vascular redundancy and sparing of the anterior and posterior most aspects of the calcarine cortex.2