Fundus fluorescein angiography (FFA) and OCT angiography (OCT-A) are both imaging modalities that reveal the retinal vasculature, but they work differently and have different clinical strengths. FFA involves injecting a fluorescent dye into a vein in the arm and photographing the retina as the dye passes through the blood vessels. It reveals areas of active vascular leakage, identifies zones of capillary non-perfusion where the ischaemia driving neovascularisation originates, and precisely maps the distribution of new vessel formation. It is particularly valuable for treatment planning before panretinal laser and for establishing the extent of ischaemia. OCT-A is non-invasive and does not require dye injection. It maps the retinal capillary plexuses using motion contrast and provides exquisite detail of the foveal avascular zone and early capillary dropout with resolution that FFA cannot match. It is increasingly used for detecting early diabetic vascular changes before they are clinically apparent, and for monitoring subtle progression. In practice, both have a role: FFA for leakage mapping and treatment planning, and OCT-A for early detection and monitoring. The choice depends on the clinical question being answered at each visit.
Written by Dr. Usha Shree, MBBS, DNB Ophthalmology, FICO, FVRS, Vitreo-Retina Specialist, Kasturi Nagar, Bengaluru. 12 years. 10,000+ patients. Phone: +91 96633 58193.
