Silent occult choroidal vascular abnormalities.
PURPOSE: To describe clinically occult choroidal vascular abnormalities that can be revealed by indocyanine green (ICG) angiography. METHODS: Out of approximately 2,700 patients who underwent ICG angiography, a lesion was incidentally observed in eight eyes of eight patients. In five patients, the ICG study included a second examination taken during artificially induced intraocular hypertension. Examinations were repeated in six patients over a follow-up period ranging from 4 months to 3 years. RESULTS: On ICG angiogram, the choroidal vasculopathy appeared as a round-oval hyperfluorescent area 2-4 disk diameters in size that was located at the temporal vascular arcades in six eyes, at the inferomacular region in one eye, and above the optic disk in one eye. The lesions were not identifiable with funduscopic, fluorescein angiographic, or ultrasonographic examination. The lesions filled at the same time as the choroidal arteries and lost fluorescence in mid-late phase of the ICG angiogram. The ICG series taken during induced intraocular hypertension showed the hyperfluorescent areas originated from choroidal arterial abnormalities giving rise to confluent hyperfluorescent patches. Draining vessels connecting the choroidal vasculopathy with a vortex vein were evidenced in three eyes. A sector of apparent choroidal hypoperfusion downstream from the lesion was present in three eyes. During the follow-up period, the lesions remained occult and with an unchanged ICG angiographic pattern in all patients. CONCLUSION: Some silent occult choroidal vascular abnormalities may be incidentally revealed by ICG angiography. These must be distinguished from ICG imaging of concomitant chorioretinal disorders.