Diagnosis of Cavernous Sinus Artenovenous Fistula by Measurement of Ocular Pulse Amplitude

Background: The ocular pulse amplitude (OPA), the difference between the maximum and minimum intraocular pressure (IOP) during the cardiac cycle, has been reported to be elevated in the eye ipsilateral to a cavernous sinus arteriovenous fistula. Methods: The OPA was measured with a pneumotonometer in three groups of patients. Patients in group 1 had no orbital disease (n = 50), patients in group 2 had either unilateral or asymmetric orbital disease (n = 30), and patients in group 3 had angiographically proven cavernous sinus arteriovenous fistulas (n = 15). Results: Patients in group 3 had a higher OPA than patients in either group 1 (P < 0.001) or group 2 (P < 0.001). The difference in OPA between an individual's eyes (ΔOPA) also was higher in patients with cavernous sinus arteriovenous fistulas than in patients without fistulas (P < 0.0001). Conclusion: A ΔOPA of more than 1.6 mmHg was 100% sensitive and 93% specific in identifying patients with cavernous sinus arteriovenous fistulas. There was no difference in ΔOPA between direct and dural cavernous sinus arteriovenous fistulas. Successful transvascular embolization of the cavernous sinus arteriovenous fistula normalized the ΔOPA by reducing the OPA on the affected side.