In the last decade, optical coherence tomography angiography (OCT-A) has “revolutionised eye care by providing high-resolution images of microvascular structures, enabling early detection and monitoring of conditions such as diabetic retinopathy [DR], macular degeneration, and glaucoma” (The Ophthalmologist, 2025). 

OCT-A allows “non-invasive, dye-free visualisation of retinal and choroidal vascular structures”, says Christiana Dinah, Consultant Ophthalmologist and Director of Research and Innovation at London North West University Healthcare NHS Trust. She says the premise is that by taking many OCT B-scans very quickly, one after another, the machine can detect very small changes caused by moving blood cells (motion contrast), which enables mapping of the blood vessels in the retina and choroid. “It therefore generates depth-resolved, layer-by-layer ‘angiograms’ co-registered with structural OCT.”

Introduced commercially around 2014, OCT-A “now underpins daily retinal diagnostics”, says Tariq Aslam, Consultant Ophthalmologist at Manchester Royal Eye Hospital (MREH) and Professor of Ophthalmology at the University of Manchester.  

He says that at MREH, OCT-A is used for routine diagnosis and follow-up of DR, neovascular age-related macular degeneration (nAMD), and many other conditions affecting retinal vasculature, such as retinal vein occlusions.  

OCT-A allows microvascular disruption or neovascular growth to be visualised long before these become clinically visible, says Tariq. “This is an insight that will be increasingly valuable for optometrists making early or follow-up assessments.”