Three patients with dural arteriovenous malformations contiguous with the cavernous sinus had marked worsening of their neuro-ophthalmic symptoms. Such clinical deterioration has been attributed traditionally to increased blood flow through the malformations into the superior ophthalmic vein. However, arteriography in all three patients and magnetic resonance imaging (MR) in two patients demonstrated thrombosis of the entire superior ophthalmic vein. All patients subsequently underwent spontaneous, complete resolution of symptoms. This report describes a clinical syndrome of paradoxical worsening of cavernous sinus malformations and indicates that MR will aid in the management of these vascular malformations.