BACKGROUND: Carotid cavernous sinus fistula may induce drastic changes in choroidal circulation secondary to elevated orbital venous pressure. CASES AND METHODS: Three patients affected by spontaneous carotid cavernous sinus fistula were studied for 3-15 months. The angioarchitecture and hemodynamics of the choroid were evaluated repeatedly by indocyanine green angiography using a montage panoramic technique. RESULTS: Choroidal vessels underwent drastic restructuring including patchy nonperfusion of the choriocapillaris, attenuation of vortex veins, preferential venous dilatations, and drainage into outflow channels near the optic disc or into anterior ciliary veins. CONCLUSIONS: Choroidal veins were very versatile in remodelling their structure and hemodynamics after sustained elevation of orbital venous pressure. The presence of numerous anastomoses between choroidal veins appeared to be a major underlying cause of this versatility. The observed remodelling of choroidal vessels seemed to be guided by the principle that the venous blood flowed toward sites of lesser pressure resistance.
BACKGROUND: Carotid cavernous sinus fistula may induce drastic changes in choroidal circulation secondary to elevated orbital venous pressure. CASES AND METHODS: Three patients affected by spontaneous carotid cavernous sinus fistula were studied for 3-15 months. The angioarchitecture and hemodynamics of the choroid were evaluated repeatedly by indocyanine green angiography using a montage panoramic technique. RESULTS: Choroidal vessels underwent drastic restructuring including patchy nonperfusion of the choriocapillaris, attenuation of vortex veins, preferential venous dilatations, and drainage into outflow channels near the optic disc or into anterior ciliary veins. CONCLUSIONS: Choroidal veins were very versatile in remodelling their structure and hemodynamics after sustained elevation of orbital venous pressure. The presence of numerous anastomoses between choroidal veins appeared to be a major underlying cause of this versatility. The observed remodelling of choroidal vessels seemed to be guided by the principle that the venous blood flowed toward sites of lesser pressure resistance.