FUNDUS ANGIOGRAPHY

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FUNDUS ANGIOGRAPHY
1. Fluorescein (FA)

• General principles

• Excitation and emission

• Filters

• Photographic technique

• Phases of normal angiogram
• Causes of dark appearance of fovea

• Causes of hyperfluorescence

• Causes of hypofluorescence

2. Indocyanine green (ICG)

• General principles

• Phases of normal angiogram

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General principles of FA
Fluorescein

• 85 bound to serum proteins

• 15 unbound free fluorescein

Inner blood-retinal barrier (retinal
capillaries)

• Impermeable to fluorescein

Outer blood-retinal barrier (zonula occludens)

• Impermeable to fluorescein

Choriocapillaris

• Permeable only to free fluorescein

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Excitation and emission
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Filters
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Photographic technique
1. Take red-free photograph
2. Inject rapidly 5 ml of 10 solution
3. Take photographs at 1 sec intervals
between 5-25 sec after injection
4. Take photographs after 10 min and 20
min, if appropriate
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Phases of normal FA
Early venous
Arteriovenous (capillary)
Arterial

• Marked lamellar venous flow

• Arterial filling

• Very early lamellar
• venous flow

Mid-venous
Late
Late venous

• Progressively weaker fluorescence

• Almost complete
• venous filling

• Complete venous
• filling

• Staining of disc

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Causes of dark appearance of fovea
Avascularity
Blockage of background choroidal fluorescence by

• Increased density of xanthophyll

• Large RPE cells with more
• melanin

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Causes of hyperfluorescence ( 1 )
RPE window defect
Pooling of dye
Under RPE (pigment epithelial detachment)
RPE atrophy (bulls eye maculopathy
Under sensory retina (central serous
retinopathy)
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Causes of hyperfluorescence (2)
Prolonged dye retention ( staining )
Leakage of dye
Associated with drusen
From new vessels (choroidal neovascularization
Into sensory retina (cystoid macular
oedema)
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Causes of hypofluorescence (1)
Blocked retinal or choroidal fluorescence

• Abnormal
• material

• Preretinal or intraretinal blood

• Blood under retinal pigment
• epithelium

• Increased
• pigment

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Causes of hypofluorescence (2)
Vascular occlusion
Loss of vascular tissue
Capillary non-perfusion (venous occlusion)
Choroideremia or high myopia
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General Principles of ICG Angiography
1. Binding

• 98 bound to proteins

• Less leakage from choriocapillaris

2. Fluorescence

• Much less than fluorescein

• Excitation peak 800 nm

• Emission at 835 nm

3. Filters

• Infrared barrier and excitation

4. Safer than fluorescein
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Phases of normal ICG angiogram (1)
Early (20 sec)
Early middle (3 min)

• Disc hypofluorescence

• Filling of watershed zone

• Poor perfusion of vertical
• (watershed) zone near disc

• Fading of choroidal arterial filling

• Prominent filling of choroidal arteries

• Prominent filling of choroidal veins

• Early filling of choroidal veins

• Filling of retinal arteries but not veins

• Filling of retinal arteries and veins

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Phases of normal ICG angiogram (2)
Late (21 min)
Late middle (6 min)

• Reduced filling of choroidal vessels

• Large choroidal and retinal vessels are
• empty

• Diffuse hyperfluorescence due to
• diffusion of dye from choriocapillaris

• Diffuse background hyperfluorescence

• Persistent filling of retinal vessels