Diagnosis of Cavernous Sinus Arteriovenous 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 less than 0.001) or group 2 (P less than 0.001). The difference in OPA between an individual's eyes (delta OPA) also was higher in patients with cavernous sinus arteriovenous fistulas than in patients without fistulas (P less than 0.0001).

Conclusion: A delta OPA 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 delta OPA between direct and dural cavernous sinus arteriovenous fistulas. Successful transvascular embolization of the cavernous sinus arteriovenous fistula normalized the delta OPA by reducing the OPA on the affected side.