Optical coherence tomography angiography: a review of the current literature

Abstract

This narrative review presents a comprehensive examination of optical coherence tomography angiography (OCTA), a non-invasive retinal vascular imaging technology, as reported in the existing literature. Building on the coherence tomography principles of standard OCT, OCTA further delineates the retinal vascular system, thus offering an advanced alternative to conventional dye-based imaging. OCTA provides high-resolution visualisation of both the superficial and deep capillary networks, an achievement previously unattainable. However, image quality may be compromised by factors such as motion artefacts or media opacities, potentially limiting the utility of OCTA in certain patient cohorts. Despite these limitations, OCTA has various potential clinical applications in managing retinal and choroidal vascular diseases. Still, given its considerable cost implications relative to current modalities, further research is warranted to justify its broader application in clinical practice.

Keywords: Ophthalmic imaging; age-related macular degeneration; diabetic retinopathy; glaucoma; optical coherence tomography; optical coherence tomography angiography; retinal conditions; retinal vein occlusion.

Figure 1.

Left eye macular optical coherence tomography angiography. The outer retina slab (cyan) shows a large branching vascular network in the subretinal space (between the retinal pigment epithelium and the photoreceptor layer) with subretinal fluid suggestive of active type 2 choroidal neovascularisation. The Angio B mode (bottom left) shows blood flow through the vascular network (blue arrow), further confirming the activity of the choroidal neovascularisation.

Figure 2.

Right eye macular optical coherence tomography angiography. The choriocapillaris slab (blue) shows a well-circumscribed vascular network in the sub-retinal pigment epithelial space suggestive of type 1 choroidal neovascularisation. The Angio B mode confirms flow within the lesion (blue arrow).

Figure 3.

Right eye, type 3 choroidal neovascularisation (retinal angiomatous proliferation), two separate foci. Flow in the Angio B mode (upper lesion) shows communication with the sub-retinal pigment epithelial space.

Figure 4.

Left eye macular optical coherence tomography angiography in a patient with superior macular branch retinal vein occlusion. The deep vascular plexus slab (green) shows a widened, irregular foveal avascular zone (red arrow), capillary drop-out (blue arrow), and telangiectatic vessels at the borders (green arrow).