Contribution of OCT angiography in angioid streaks

Abstract

Purpose: To study the appearance of angioid streaks (AS) in swept source optical coherence tomography angiography.

Methods: Retrospective observational study of 16 patients (31 eyes) with various stages of AS. All included patients underwent complete ophthalmologic examinations including best-corrected visual acuity (BCVA), slit-lamp examination, indirect ophthalmoscopy and fundus photography. Swept source optical coherence tomography (SS-OCT), OCT angiography (OCT-A) and fluorescein angiography were also performed.

Results: En face OCT detected hyper-reflective points in 65% of cases, with a choriocapillaris (CC) shadow on the corresponding OCT-A. Diffuse CC rarefaction was detected in 94%. In eyes without neovascular complications, streaks were visible as a hyposignal in the outer retina. An irregular vascular network (IVN) was detected in 80% of eyes. It filled the spaces between the AS and corresponded to flat elevation of the retinal pigmentary epithelium. Twenty-four eyes had choroidal neovascularization (CNV). CNV was type 1 in 8%, type 2 in 43%, mixed in 20% and unclassified in 29% because of a large scar. We found multiple sites of CNV in 8% of cases. CNV shape was tangled in 66% and in 2 eyes with newly diagnosed CNV. OCT-A showed a perilesional halo around new CNV. The morphology and configuration of neovascular network follow the IVN and the path of the AS and arises in proximity to sites of BM disruption.

Conclusion: OCT-A allows early detection and monitoring of AS and their neovascular complications. It shows CC rarefaction, IVN and a predominantly tangled shape of CNV. However, there are some limitations associated with difficulty in characterizing signs of CNV activity.

Keywords: Angioid streaks; Choriocapillaris rarefaction; Choroidal neovascularization; En face OCT; Irregular vascular network; Néovascularisation choroïdienne; Optical coherence tomography; Optical coherence tomography angiography; Raréfaction choriocapillaire; Réseau vasculaire irrégulier; Stries angioïdes; Tomographie en cohérence optique OCT en face; Tomographie en cohérence optique angiographie.