Teaching NeuroImages: Sonographic "retrobulbar spot sign" in differentiating etiologies of sudden visual loss

A 61-year-old vascular patient presented with headache and subacute blindness in the left eye. Remaining American College of Rheumatology criteria were negative. Sonography of the temporal artery revealed no halo sign, but due to low sensitivity, vasculitis could not be excluded.(1) Transorbital examination revealed hyperechogenic retrobulbar spot sign (figure), which is highly specific for embolic occlusion of the central retinal artery.(2) Comprehensive diagnostic workup revealed paroxysmal atrial fibrillation as a putative cause for the embolus and no evidence for vasculitis. Thus, potentially harmful thrombogenic administration of steroids could be avoided. Transorbital sonography may help in cases of sudden visual loss of unclear etiology.