OCT Angiography: An Upcoming Non-invasive Tool for Diagnosis of Age-related Macular Degeneration

Abstract

Purpose: To review the most recent findings, characteristics, faults and future perspectives of optical coherence tomography angiography (OCTA) in age-related macular degeneration (AMD).

Recent findings: In dry AMD, OCTA is useful on the evaluation of choriocapillaris perfusion and detection of naïve quiescent non-exudative choroidal neovascularization (CNV). In wet AMD, OCTA can provide detailed anatomic and morphologic information of CNVs, which may help to understand why and how they develop and become active. In other hand, the many artifacts present in OCTA images may lead to misinterpretation and misdiagnosis.

Summary: OCTA is a still developing technology that is able to provide a large amount of anatomic, functional and morphologic information in macular diseases and, particularly, AMD. As the technology evolves, the need of dye-based modalities tends to decrease.

Keywords: age-related macular degeneration (AMD); optical coherence tomography angiography (OCTA).

Figure 1

Spectral-domain (SD) optical coherence tomography angiography of a type 1 choroidal neovascularization from one eye of patient with exudative age-related macular degeneration. (A) 3×3 mm en face flow angiogram extracted from the slab shown on C revealing the neovascular network of a type 1 choroidal neovascularization (CNV); (B) 6×6 mm en face flow angiogram extracted from the slab shown on D. Differently from the 3×3 mm angiogram shown on A, the CNV is almost indistinguishable from the surrounding choriocapillaris due to lower resolution of the 6×6 angiogram. (C and D) B-scan from which the 3×3 and 6×6 mm angiogram on A and C, respectively, were extracted demonstrating the boundaries of the slab; top boundary under the retinal pigment epithelium and bottom boundary under the Bruch’s membrane.

Figure 2

En face flow angiograms from diferente morphologic patterns of choroidal neovascularization (CNV). (A) Medusa shape, showing vessels radiating from the center to all directions; (B) seafan shape, presenting with vessels branching to one side of the main trunk; (C) glomerular shape, defined as globular structures with intertwined vessels; and (D) “dead tree” shape, composed by a main pruned vascular trunk.