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FFA & ICG. Ewan McCallum GHH 15/7/14. Overview. FFA & ICG Background Examples Background Examples. FFA. 20% free in plasma Excited by blue light to emit yellow light Cannot diffuse through tight junctions RPE Retinal vessel endothelium
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FFA & ICG Ewan McCallum GHH 15/7/14
Overview • FFA & ICG • Background • Examples • Background • Examples
FFA • 20% free in plasma • Excited by blue light to emit yellow light • Cannot diffuse through tight junctions • RPE • Retinal vessel endothelium • NB – fluorescein leaks freely into aq/vit therefore white structures pseudofluoresce
FFA • 5 phases • Choroidal – v brief as leaks fast • Arterial – CRA fills 1 sec later • Capillary – perifoveal network most visible due to luteal pigment. 500micron FAZ • Venous – early laminar flow • Late – 10-15mins dye only left in structures where it has leaked. Drusen, window defects and inactive scars fade, i.e show up active disease
ICG • 800nm wavelength, penetrates retinal layers • Tightly bound to plasma proteins so stays in vessels • Allows better view of choroidal circulation
Polypoidalchoroidalvasculopathy • Sub type of AMD • 15% of all ‘CNV’ • Steep walled haemorrhagic PED on OCT • PDT +/- anti VEGF best • Need ICG to diagnose most (wide angle to pick up more)
Retinal angiomatous proliferations • Sub type of AMD • Large serous PEDs • extensive areas of small drusen • leak aggressively • Respond poorly to anti VEGF • NB patient expectation • Up to 100% of fellow eyes affected • 37% within 3 years
MACTEL • Not an ‘AMD’ • Important as does not respond to anti VEGF
CSR • Can be confused with AMD as exudative maculopathy • Especially if chronic/recurrent • Chronic can develop into nAMD or IPCV