The Diagnosis of Carotid-Cavernous Sinus Fistulas by Ocular Pulse Amplitude

We used a pneumotonometer to determine the diagnostic value of the ocular pulse amplitude (OPA) in three groups of patients. The difference in OPA between eyes ( OPA) was determined for patients with no orbital disease (group 1, n=50), patients with orbital disease (group 2, n=30) and. patients with angiographically proven carotid cavernous sinus fistula (group 3, n=15). OPAwas 0.47 (SD=.37) in group 1, 0.30 (SD=.25) in group 2 and 3.54 (SD=1.39) in group 3. We could not demonstrate a statistically significant difference in OPA between group 1 and group 2. There was a significant difference between group 3 and both group 1 (p .001) and group 2 (p .001). Furthermore, no patient in groups 1 or 2 had an OPA greater than 1.5 whereas 14 of 15 patients (93%) in group 3 did.