FAF Flashcards
Lipofusion is a
photoreceptors outer segment phagocytosis byproduct.
lipofusion accumulates in a. RPE b. Photoreceptor c. ganglion cells
a. RPE (and eventually in outer retinal layers) -accumulates naturally with age -too much of this indicates retinal pathology (activity in rpe cell death process) -Too little of this can indicate rpe death
we view lipofuscin via
FAF (It absorbs 500nm-800nm)
what two ways we can accomplish autofluorescing effect? (one we do in lab)
- Extremely bright flash from cannon fundus photography 2.confocal scanning laser ophthalmoscope
The FAF images from cannon are similiar to
similiar to Red-Free and IVFA ….BUT FAF gets you view of lipofusin
Hyper AF=
metabolically sick RPE (too much LF )
Hypo AF= means what about the RPE
RPE DEAD or not present (Lf is gone), signal blockage. cuz LF is supposed to give me fluroscene. light passes through emitting light. but if its not passing there either that RPE is not there or there is a signal blockage somewhere. giving me a dark (HYPO AF)
Guaranteed exam question. How does age affect FAF?
older you get the more metabolic activity you have. =hyperfluorescene
How does a cataract or corneal dx affect FAF? guaranteed exam
darker FAF=hypofluorescene dont get confused with background.
FAF intensity (hypofluroscene or HYPERflourscene) is affected by what type of device used. .
T/F
true , it depends on the modality.
FAF stands for
Fundus AutoFluorescence (FAF)
Ocular fluorophores (retinal fluorophores) are ….. Examples include
Retinal molecules that are exhibit fluorescence emission when excited. -Lipofusion (increases af) -ONH drusen (increases af) retinal molecules that absorb fluorescene -Rhodopsin (decreases AF)
What’s the main difference between Fundus AUTOFluorescence and fluorescein angiography?
FUNDUS AUTOFluorescence is not dependent on circulation like fluorescein angiography
What are the FUNDUS AUTOFluorescence image intensity variables? I.e. what can make the intensity FAF images vary? exam question!
The persons age, Media opacity like a cataract or corneal sizes Pupil size The type of device used - scanning laser phthalmoscope vs fundus camera-based system
What does a healthy FUNDUS AUTOFLUROscene look like?
Insert pic.
What areas are supposed to be dark on FUNDUS AUTOFLUROscene?
Blood vessels because of signal absorption from blood Fovea- because of signal absorption from macular luteal pigment ONH- because of absorption and absence of RPE
What is the gray/grainy appearance on A FUNDUS AUTOFLUORSCENE represent ?
It represents a mild HYPER-FLUORSCENCE (normal levels of lipofuscin in RPE cells )
This pic is an image of a REDUCED or INCREASED AF?
Reduced AF because it has a dark spot representing less signal emission. this is signal absorption .
A reduced AUTOFLUROSCENE represents a A. Hypo AF B. HYPER AF
A. HYPO AF
What can cause a HYPO - FAF? Exam question !!
- Reduced or absent RPE (esp. RPE atrophy {geographic atrophy, central serous chorioretinopathy, hereditary}, RPE tear, reduced visual cycle,) 2. Anterior material blocking RPE (esp- hyperpigmentation {macular pigments, intraretinal &/or sub retinal hemorrhage}, scar tissue, INTRARETINAL AND/OR SUBRETINAL HEMORRHAGE)
*Exam question What can cause an INCREASED AUTOFLUROSCENE? Aka Hyper AF
Drusen Older hemorrhages Excess concentrations of lipofuscin IN RPE (lipofuscinopathies , RPE tear: retracted border) like stargardt dz, pattern dystrophies SUB-retinal autofluorescent material, Window defect (loss of luteal or photo pigment ) Other autofluorescent material
Hypo AF means darker or lighter signal?
darker