OCTA imaging, or optical coherence tomography angiography, is a non-invasive technique that visualises blood flow in retinal and choroidal vessels without dye injection. It uses motion contrast from repeated OCT scans to map the vascular network.
How it Works
The device acquires multiple OCT scans at the same location and detects changes caused by moving blood cells. Software constructs depth-resolved images of capillary plexuses in and below the retina.
- Provides en face views of superficial and deep vascular layers
- Avoids intravenous dye and its systemic risks
- Sensitive to flow in small vessels but may miss very slow or turbulent flow
- Artifacts from motion or shadowing require careful interpretation
Clinical Applications
OCTA helps evaluate diseases such as macular degeneration, diabetic retinopathy, and retinal vascular occlusions by showing areas of non-perfusion, neovascular networks, and capillary rarefaction. It is also used in glaucoma research to study perfusion around the optic nerve.
- Allows quantitative analysis of vessel density and flow indices
- Useful for monitoring response to therapies targeting neovascularisation
- Complementary to structural OCT and conventional angiography
- Image quality depends on fixation and media clarity
