Indocyanine green angiographic and optical coherence tomographic findings support classification of polypoidal choroidal vasculopathy into two types

Abstract

Purpose: We assessed the characteristic indocyanine green angiographic (ICGA) and spectral domain optical coherence tomographic (SD-OCT) findings of two types of polypoidal choroidal vasculopathy (PCV), distinguishable by different filling patterns on ICGA.

Methods: Thirty-one eyes with PCV were classified into types 1 and 2 based on ICGA findings of either the presence or absence of both a feeder and a draining vessel. Characteristic ICGA findings were evaluated for each type of PCV. Spectral domain optical coherence tomographic images of the 31 eyes were also used to compare the two types of PCV.

Results: Both a feeder and a draining vessel were observed in 13 eyes (type 1). Eighteen eyes had neither feeder nor draining vessels (type 2). In PCV type 1, a break in the highly reflective line thought to be Bruch's membrane was detected, corresponding to the feeder vessel in-growth site on SD-OCT. This line was straight. In PCV type 2, the highly reflective line exhibited irregular thickness and had highly reflective substances adhering to its lower portion. It curved downward and became increasingly obscure, ultimately disappearing at a point corresponding to the site at which network vessel filling began. The mean subfoveal choroidal thicknesses in eyes with PCV type 1 and PCV type 2 were 199 ± 65 and 288 ± 98 μm, respectively.

Conclusions: Our observations support the existence of two distinct types of PCV. The first type represents choroidal neovascularization, whilst the second type involves choroidal vasculature abnormalities.

Keywords: choroidal neovascularization; choroidal vasculature abnormality; indocyanine green angiography; optical coherence tomography; polypoidal choroidal vasculopathy.