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JAE JUNG LEE, Jin Hwan Ahn, Hanjo Kwon, Sung Who Park, Ji Eun E Lee; Investigation of early choroidal hypofluorescence in indocyanine green angiography using multimodal imaging. Invest. Ophthalmol. Vis. Sci. 2018;59(9):4654.
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Choroidal circulation is related to several retinal diseases, including age-related macular degeneration and central serous chorioretinopathy. Early choroidal hypofluorescence (ECH), so called choroidal watershed zone (CWZ) was known as a sign of compromised circulation and reportedly associated with development of choroidal neovascularization. Nevertheless, the pathologic role of ECH is still under debate. We investigated ECH observed in indocyanine green angiography (ICGA) using multimodal imaging in normal subjects.
The present study was retrospective review of the prospective cohort recruited to classify CWZs. The original cohort was collected as two different age groups; 20-45 years old and 50-70 years old. The young group consisted of normal cohort, and the old group was composed of the contralateral eyes of epiretinal membrane patients. They were regrouped into three age groups; 20-40 (Young), 40-60 (Middle) and 60- (Old). ECH was defined as the local hypofluorescence compared to the surrounding choroid observed before the choroidal fluorescence became even in ICGA. En-face images of the Sattler layer, the transit zone and the Haller layer were generated from the volume scan obtained using swept-source optical coherence tomography. The causes of the ECH was analyzed by comparing vascular pattern depicted in ICGA and en face images.
Young, Middle and Old group had 26, 15 and 20 subjects, respectively. Duration of ECH was 4.9s (range; 3-7s) in Young group, 6.1s (4-12s) in Middle group and 7.4s (3-16s) in Old group, and was significantly longer in the older age groups (P=0.002). The choroidal thickness in the central 1-mm area was significantly thinner (P=0.020), and the depth of the transit zone was significantly shallower in older groups (P=0.002). ECH was classified into 5 different types; choroidal watershed zones, delayed arterial perfusion, filling defect by large choroidal vein, venous congestion and vascular paucity.
Various mechanisms existed for ECH other than a choroidal watershed zone. Prolongation of ECH and thinning of the choroid related to increasing age suggests that the choroidal circulation is compromised in elder people. ECH would be a marker of the compromised circulation of the choroid.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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