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DIT FAF EXAM WITH CORRECT ANSWERS 100% VERIFIED!!, Exams of Advanced Education

DIT FAF EXAM WITH CORRECT ANSWERS 100% VERIFIED!!

Typology: Exams

2024/2025

Available from 07/05/2025

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DIT FAF EXAM WITH CORRECT ANSWERS 100% VERIFIED!!
FAF
used to record fluorescence that may occur naturally in the eye or accumulate as a
byproduct of a disease process
autofluorescence
used to distinguish this type of fluorescence from that which occurs from administration
of fluorescent dyes such as fluorescein or indocyanine green
fluorophores
chemical structures that possess
fluorescent properties when exposed to light of an appropriate wavelength
Fluorescence occurs
when these molecules absorb electromagnetic energy,
excites them to a higher energy state triggers the emission of light at wavelengths
longer than the excitation source.
In the Eye Exhibit natural (measurable/significant) fluorescence
lipofuscin pigments in the retina,
Optic nerve drusen,
astrocytic hamartomas,
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pf5
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pf9
pfa
pfd
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FAF

used to record fluorescence that may occur naturally in the eye or accumulate as a byproduct of a disease process

autofluorescence used to distinguish this type of fluorescence from that which occurs from administration of fluorescent dyes such as fluorescein or indocyanine green

fluorophores chemical structures that possess fluorescent properties when exposed to light of an appropriate wavelength

Fluorescence occurs when these molecules absorb electromagnetic energy, excites them to a higher energy state→ triggers the emission of light at wavelengths longer than the excitation source.

In the Eye Exhibit natural (measurable/significant) fluorescence lipofuscin pigments in the retina, Optic nerve drusen, astrocytic hamartomas,

aging crystalline lens (vs. 'normal' crystalline lens)

RPE

Single layer of polygonal cells, Located between the choroid & neuro-sensory retina, Multiple functions

RPE multiple functions responsible for phagocytosis and lysosomal breakdown of pigmented outer segments of photoreceptors,

allows the renewal process necessary to maintain photoreceptor excitability

RPE lipofuscin contains at least ___ different fluorophores 10

Retinoid Fluorophores emission spectra green, golden yellow, yellow-green, and orange-red

Lipofuscin the major source of fundus autofluorescence,

aging and ocular disease

LF can be made to fluoresce by a fairly broad range of wavelengths, about 500 to 800 nm, Peak emission about 630 nm (600 - 610 nm),

After excitation the molecule will spontaneously release a photon of light of a somewhat longer wavelength

lipofuscin is a dominant macular fluorophore

lipofuscin absorption absorbs blue light with a peak excitation wavelength of 470 nm, emits yellow-green light at a peak wavelength of 600-610 nm

Melanin an ocular pigment located in the both RPE cells and in uveal melanocytes, rimary fluorophore in near-infrared

autofluorescence

melanin in the fundus is distributed primarily in the fovea, macula, and periphery

melanin peak excitation 787 nm

melanin on conventional FAF absorbs the short-wavelegth excitation beam (decreasing the overall autofluorescent signal)

Lipofuscin based autofluorescence is also known as blue autofluorescence (BAF), short wave autofluorescence (SWAF), or simply (fundus) autofluorescence. FAF; AF

Melanin based autofluorescence is also known as near- infrared autofluorescence. (NIRAF)

FAF Images

Both BAF and NIRAF can be differentiated from the red-free images by

he darker appearance of the optic disc and retinal blood vessels compared to the red-free images.

Commercially available FAF systems include fundus cameras, confocal scanning laser ophthalmoscopes (cSLO), ultra-widefield technologies

Limitations/challenges of FAF

Signal strength: Low signal strength (two orders of magnitude less than the peak signal of fluorescein angiography), Interpreting the image: variable quality and intensity, phenomenon of photoreceptor bleaching. Pt discomfort from blue-light excitation beam. Lacking formal studies demonstrating the specific safety/adverse effects of FAF

FAF utilizes the fluorescent properties of lipofuscin within the RPE to create an image

Lipofuscin byproduct of

lysosomal breakdown of photoreceptor outer segments

Density map of lipofuscin' SWAF brighter areas representing regions of increased lipofuscin density, many retinal pathologies often lead to RPE dysfunction and an accumulation of lipofuscin, abnormal patterns of AF act as markers for retinal disease

Common conditions - FAF usefulness Retinal Dystrophies, macular telangiectasis, pharmacologix toxicity, AMD

retinal dystrophies Viteliform dystrophy (Best's disease), Stargardt disease, cone and cone-rod dystrophies

hyperfluorescent Areas of excess lipofuscin (LF) accumulation

Fresh intraretinal and subretinal hemorrhages,

Intraretinal and subretinal lipid,

Fibrosis, scar tissue, or borders of laser scars,

Retinal vessels,

Luteal pigment (lutein and zeaxanthin)

increased FAF(SWAF) signal commonly due to lipofuscin accumulation in the RPE, presence of other fluorophores not in the RPE: drusen - (including those in the optic nerve head) or older hemorrhages, lack of absorbing material, artifactsLipofuscinopathies

Lipofuscinopathies including Stargardt disease, Best disease, and adult vitelliform macular dystrophy

Age-related macular degeneration RPE in the junctional zone preceding enlargement of occurrence of geographic atrophy

Subretinal fluid leading to separation of the outer segments of the photoreceptors from the underlying RPE, which leads to improper outer segment turnover

Disease Markers lines of evidence suggest that excessive lipofuscin accumulation represents a common downstream pathogenetic pathway in various hereditary and complex retinal diseases

Changes in the FAF signal may allow for an estimate of the extent of damage, diagnose sequalae such as secondary CNV (choroidal neovascularization), learn more about the inflammatory process, possibly anticipate future problems caused by disease

Clinical applications noninvasive diagnosis, monitoring disease progression, explaining visual loss (Explaining visual symptoms)

FAF provides functional information about retinal cells useful for almost any fundus disorder.

Choroidal nevus overlying drusen, hypoautofluorescence, location within the choroid, causing deep shadowing overlying tiny drusen, and no subretinal fluid on OCT

Pigmented choroidal melanoma ipofuscin (orange pigment)-is a risk factor for tumor growth, FAF photography: ipofuscin is not observed clinically, subretinal fluid - hyper

Retinal dystrophies and degenerations show abnormal autofluorescence

retinal dystrophies such as retinitis pigmentosa demonstrate areas of both hyper- and hypofluorescence, a sign that the retina is 'burning out'

Hydroxychloroquine maculopathy A ring of hyper-autofluorescence along with parafoveal dark areas will be visible, especially true in moderate and later stages

Damage from hydroxychloroquine and chloroquine toxicity appears to primarily affect the perifoveal photoreceptors, with secondary damage to the RPE

early hydroxychloroquine and chloroquine toxicity changes are noted on SD-OCT and mfERG, increased AF is seen with FAF likely due to early RPE dysfunction.

late finding of hydroxychloroquine and chloroquine toxicity include atrophy and decreased AF.

Retinal Detachment Hyperfluorescence in areas immediately adjacent to a retinal detachment can demarcate its extent

Central serous chorioretinopathy (CSC) extent seen with autofluorescence, not just in the area of the subretinal fluid but also in other parts of the macula or even the other eye

Adaptive optics SLO describes the use of wavefront sensors to sense aberrations of ocular optics, and to use deformable mirrors to compensate for the aberrations to enhance retinal imaging