ffa & icg

FFA & ICG

Ewan McCallumGHH

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 – peri foveal 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

Polypoidal choroidal vasculopathy

• 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

Diabetes