Lecture 1/2 - Diagnostics Flashcards
What is red light/filter used for?
travels the furthest - pigmentary disturbances, choroidal ruptures, choroidal nevi, choroidal melanomas
What is blue light/filter used for?
NFL, ILM, ERM, retinal folds, cysts
What is green light/filter used for?
retinal vasculature, hemorrhages, drusen, exudates
what are the 4 parts to the early phase in FA?
choroidal flush, arterial phase, arteriovenous phase, and venous phase
when is the choroidal flush?
10-15 seconds after injection, dye in choriocapillaries
when is the arterial phase?
1-2 seconds after choroid - about 12 seconds
a delay may indicate injection or circulatory problems = heart or peripheral disease
when is the venous phase?
about 30 seconds after injection - maximum vessel filing
what are the 3 main phases of FA?
early phase, mid phase (recirculation phase) and late phase
when does the mid phase occur?
2-4 minutes - veins and arteries remain roughly equal in brightness
when does the late phase occur?
7-15 minutes - gradual elimination of dye from retinal and choroidal vasculature (late staining of optic disc is normal)
what are the 2 main causes of hypofluorescence?
vascular filling defect or blockage
if you use a red-free filter to view a dark spot on the retina and it disappears, what was it?
choroidal nevus (CHRPE will remain with red-free)
what 2 conditions can cause autofluorescence (or preinjection fluorescence)?
optic nerve drusen and optic nerve hemartoma
what causes pseudofluorescence?
poorly matched filters
what can cause early hyperflorescence in the retina?
abnormal vessels = tortuosity, dilation, anastomosis, neo, aneurysms, telangiectasia, tumor vessels
what can cause early hyperflorescence in the choroid?
PE window defect = atrophy or congenital
Abnormal vessels = subretinal neo, inflammation, tumor vessels
what can cause late hyperflorescence in the vitreous?
neo, inflammation, tumors
what can cause late hyperflorescence in the retina?
cystoid edema or non-cystic edema
what can cause late hyperflorescence in the choroid?
pooling or staining
what is leakage hyperfluorescence?
seepage of NaFl, increases in intensity and margins blur in late phase (Ex: CNVM, DME, Neo)
what is staining hyperfluorescence?
dye enters tissue and it retains it - intensity increases during transit but then stays the same, margins are distinct (Ex: scar, drusen, optic nerve tissue or sclera)
what is pooling hyperfluorescence?
accumulation of dye in a fluid-filled space in the retina or choroid, margins are distinct (Ex: RPE detachment in CSR)
what is transmission/window defect hyperfluorescence?
increased normal choroidal fluorescence through RPE defects or loss of pigment - dye stays in choroid, does not enter retina (Ex: macular hole or RPE loss)
how is ICG different than NaFl?
higher molecular weight, remains in larger blood vessels (cannot pass through choriocapillaris fenestrations) and is not blocked by melanin/xanthophyll
