FFA and ICG Angiography Patterns: Quick Reference Card
Last updated: October 2026
Read an angiogram by phase, then classify every abnormality as too bright (hyperfluorescence) or too dark (hypofluorescence), and decide why.
FFA phases (approximate timings after injection)
| Phase | Timing | What you see |
|---|---|---|
| Choroidal (pre-arterial) | About 8–12 s | Patchy choroidal flush; a cilioretinal artery fills now |
| Arterial | About 1 s after choroidal | Retinal arteries fill |
| Arteriovenous (capillary) | A few seconds later | Capillaries fill; laminar flow along the veins |
| Venous | About 20–30 s | Veins fill completely; maximum vessel fluorescence; foveal avascular zone well seen |
| Late (recirculation) | About 5–10 minutes | Dye leaves the vessels: leakage, staining and pooling show up now |
A delayed arm-to-retina time or arterial filling suggests carotid disease or artery occlusion. Delayed venous filling suggests vein occlusion or ocular ischaemic syndrome.
Hyperfluorescence: why is it too bright?
| Mechanism | Behaviour over time | Examples |
|---|---|---|
| Window (transmission) defect | Appears early with the choroidal flush, fades late; size and shape stay the same | RPE atrophy (geographic atrophy, old scars), macular hole |
| Leakage | Increases in size and brightness with fuzzy margins | Classic CNV (lacy, early), occult CNV (stippled, late), CME (petaloid or honeycomb), disc swelling, neovascularisation elsewhere |
| Pooling | Fills a defined space; brightness increases, borders stay sharp | Serous PED, CSCR (ink-blot or smoke-stack leak) |
| Staining | Late fluorescence of tissue without leakage | Drusen, scars, sclera, disc tissue, vessel walls in vasculitis |
| Abnormal vessels | Early, well-defined | Tumour vessels, telangiectasia (Coats, MacTel), shunts |
| Autofluorescence and pseudofluorescence | Visible before dye injection | Disc drusen and astrocytic hamartoma (autofluorescence); mismatched filters (pseudofluorescence) |
Hypofluorescence: why is it too dark?
| Mechanism | Examples |
|---|---|
| Blocked fluorescence (something in front) | Haemorrhage (retinal blocks retinal vessels; subretinal blocks choroid), pigment, lipofuscin (Stargardt "dark choroid"), exudate, media opacity |
| Filling defect (no perfusion) | Capillary non-perfusion (diabetic retinopathy, RVO), artery occlusion, choroidal infarcts (Elschnig spots), choroideraemia, choroidal ischaemia |
ICG angiography: when and what
| Question | ICG finding |
|---|---|
| Polypoidal choroidal vasculopathy? | Early focal hyperfluorescent polyps with a branching vascular network (the diagnostic standard; EVEREST criteria) |
| Occult CNV or retinal angiomatous proliferation (RAP)? | Late plaque (occult CNV) or a focal "hot spot" (RAP) |
| CSCR or pachychoroid? | Mid-phase choroidal hyperpermeability and dilated choroidal vessels |
| Choroiditis (white dot syndromes, VKH, sympathetic ophthalmia, birdshot)? | Hypofluorescent dark dots in the intermediate and late phases, often more numerous than the visible lesions |
| Choroidal tumours? | Haemangioma: very early intense filling with late "washout". Melanoma: variable, with intrinsic circulation. |
ICG is about 98% protein-bound and fluoresces in the near-infrared, so it passes through pigment, blood and exudate and stays inside the choriocapillaris, which is why it shows the choroid better than fluorescein.
Safety: fluorescein commonly causes nausea and yellow skin and urine; anaphylaxis is rare but real, so keep a resuscitation kit ready. ICG contains iodide: take care with iodine allergy, and avoid it in pregnancy unless essential.
Related: FFA indications, ICG angiography indications, CSCR and the OCT macula card.
Key sources
- AAO BCSC Section 12: Retina and Vitreous (current edition), chapter on diagnostic approach
- Koh A et al. EVEREST study: ICGA-guided photodynamic therapy for polypoidal choroidal vasculopathy. Retina 2012;32:1453–64
- Kwiterovich KA et al. Frequency of adverse systemic reactions after fluorescein angiography. Ophthalmology 1991;98:1139–42
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