Abstract
Abstract: :
Purpose: To describe the angioarchitecture of choroidal drainage in normal subjects using indocyanine green (ICG) angiography. Methods: Thirty-six eyes of 33 consecutive healthy volunteers ranging in age from 21 to 81 years (50.0±18.2; mean±standard deviation). ICG angiography was performed with a modified Topcon fundus ICG camera (TRC 50IL, Tokyo, Japan). Montage images covering all areas of the observable fundus were obtained during the venous phase of the ICG angiogram. Results: Of 36 eyes examined, 27 eyes (75%) had no obvious venous watershed zone identifiable on ICG angiography. Eighteen eyes (50%) did show a preferential route of choroidal drainage of the macular region. Twelve of the 18 eyes with a preferential drainage route drained superotemporally, the remaining 6 eye drained by either an inferotemporal or superonasal route. A preferential macular drainage route was identified with equal frequency in young and old subjects. Conclusions: We present anatomical evidence that the distribution of choroidal venous system drainage is asymmetric in half of normal individuals. The relative frequency of a preferential drainage route in a group of normal subjects and the equal distribution in young and old subjects indicates that this anatomical finding is neither pathologic nor attributable to aging. We also present anatomical evidence that the choroidal venous system lacks ICG identifiable venous watersheds in a majority of normal human subjects.
Keywords: imaging/image analysis: clinical • choroid • anatomy