Limits...
Fundus Autofluorescence and RPE Lipofuscin in Age-Related Macular Degeneration.

Sparrow JR, Duncker T - J Clin Med (2014)

Bottom Line: SW-AF imaging is currently used in the clinical management of retinal disorders and the advantages of NIR-AF are increasingly recognized.Here we visit the damaging properties of RPE lipofuscin that could be significant when expressed on a background of genetic susceptibility.To advance interpretations of disease-related patterns of fundus AF in AMD, we also consider the photochemical and spectrophotometric features of the lipofuscin compounds responsible for generating the fluorescence emission.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, Columbia University Medical Center, 635 W. 165th Street, New York, NY 10032, USA ; Department of Pathology and Cell Biology, Columbia University Medical Center, 630 168th Street, New York, NY 10032, USA.

ABSTRACT
Genes that increase susceptibility to age-related macular degeneration (AMD) have been identified; however, since many individuals carrying these risk alleles do not develop disease, other contributors are involved. One additional factor, long implicated in the pathogenesis of AMD, is the lipofuscin of retinal pigment epithelium (RPE). The fluorophores that constitute RPE lipofuscin also serve as a source of autofluorescence (AF) that can be imaged by confocal laser ophthalmoscopy. The AF originating from lipofuscin is excited by the delivery of short wavelength (SW) light. A second autofluorescence is emitted from the melanin of RPE (and choroid) upon near-infrared (NIR-AF) excitation. SW-AF imaging is currently used in the clinical management of retinal disorders and the advantages of NIR-AF are increasingly recognized. Here we visit the damaging properties of RPE lipofuscin that could be significant when expressed on a background of genetic susceptibility. To advance interpretations of disease-related patterns of fundus AF in AMD, we also consider the photochemical and spectrophotometric features of the lipofuscin compounds responsible for generating the fluorescence emission.

No MeSH data available.


Related in: MedlinePlus

Quantitative fundus autofluorescence (qAF) in healthy human eyes. Short-wavelength fundus AF images (top row) and corresponding color-coded qAF images (bottom row) at the ages indicated. Lower qAF values are coded in blue and higher qAF values as orange (color scale). Fundus autofluorescence intensities increase with age and the highest levels occur in superior-temporal fundus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4358814&req=5

Figure 6: Quantitative fundus autofluorescence (qAF) in healthy human eyes. Short-wavelength fundus AF images (top row) and corresponding color-coded qAF images (bottom row) at the ages indicated. Lower qAF values are coded in blue and higher qAF values as orange (color scale). Fundus autofluorescence intensities increase with age and the highest levels occur in superior-temporal fundus.

Mentions: When RPE lipofuscin is assayed by recording fluorescence in histological sections of human retina, the signal is found to increase from central fovea to perifovea and after peaking at an eccentricity of ~8°, it decreases towards the periphery [10, 78]. A similar pattern has been observed with quantitative fundus autofluorescence (qAF) (Figure 6); at an eccentricity of 10°, qAF is approximately 95% of that measured centrally [79]. Reduced foveal fundus autofluorescence is due in large part to absorption of the exciting light by macular pigment and to the higher optical density of melanin in central RPE [17]. By fundus spectrophotometry, qAF and fluorescence photomicroscopy [45], the highest levels of RPE lipofucin in healthy eyes have been observed perifoveally in superior-temporal retina (Figure 6) [44]. Unexpectedly, this pattern was not replicated in another study relying on fluorescence measurements in flat-mounted human cadaver eyes [80].


Fundus Autofluorescence and RPE Lipofuscin in Age-Related Macular Degeneration.

Sparrow JR, Duncker T - J Clin Med (2014)

Quantitative fundus autofluorescence (qAF) in healthy human eyes. Short-wavelength fundus AF images (top row) and corresponding color-coded qAF images (bottom row) at the ages indicated. Lower qAF values are coded in blue and higher qAF values as orange (color scale). Fundus autofluorescence intensities increase with age and the highest levels occur in superior-temporal fundus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4358814&req=5

Figure 6: Quantitative fundus autofluorescence (qAF) in healthy human eyes. Short-wavelength fundus AF images (top row) and corresponding color-coded qAF images (bottom row) at the ages indicated. Lower qAF values are coded in blue and higher qAF values as orange (color scale). Fundus autofluorescence intensities increase with age and the highest levels occur in superior-temporal fundus.
Mentions: When RPE lipofuscin is assayed by recording fluorescence in histological sections of human retina, the signal is found to increase from central fovea to perifovea and after peaking at an eccentricity of ~8°, it decreases towards the periphery [10, 78]. A similar pattern has been observed with quantitative fundus autofluorescence (qAF) (Figure 6); at an eccentricity of 10°, qAF is approximately 95% of that measured centrally [79]. Reduced foveal fundus autofluorescence is due in large part to absorption of the exciting light by macular pigment and to the higher optical density of melanin in central RPE [17]. By fundus spectrophotometry, qAF and fluorescence photomicroscopy [45], the highest levels of RPE lipofucin in healthy eyes have been observed perifoveally in superior-temporal retina (Figure 6) [44]. Unexpectedly, this pattern was not replicated in another study relying on fluorescence measurements in flat-mounted human cadaver eyes [80].

Bottom Line: SW-AF imaging is currently used in the clinical management of retinal disorders and the advantages of NIR-AF are increasingly recognized.Here we visit the damaging properties of RPE lipofuscin that could be significant when expressed on a background of genetic susceptibility.To advance interpretations of disease-related patterns of fundus AF in AMD, we also consider the photochemical and spectrophotometric features of the lipofuscin compounds responsible for generating the fluorescence emission.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, Columbia University Medical Center, 635 W. 165th Street, New York, NY 10032, USA ; Department of Pathology and Cell Biology, Columbia University Medical Center, 630 168th Street, New York, NY 10032, USA.

ABSTRACT
Genes that increase susceptibility to age-related macular degeneration (AMD) have been identified; however, since many individuals carrying these risk alleles do not develop disease, other contributors are involved. One additional factor, long implicated in the pathogenesis of AMD, is the lipofuscin of retinal pigment epithelium (RPE). The fluorophores that constitute RPE lipofuscin also serve as a source of autofluorescence (AF) that can be imaged by confocal laser ophthalmoscopy. The AF originating from lipofuscin is excited by the delivery of short wavelength (SW) light. A second autofluorescence is emitted from the melanin of RPE (and choroid) upon near-infrared (NIR-AF) excitation. SW-AF imaging is currently used in the clinical management of retinal disorders and the advantages of NIR-AF are increasingly recognized. Here we visit the damaging properties of RPE lipofuscin that could be significant when expressed on a background of genetic susceptibility. To advance interpretations of disease-related patterns of fundus AF in AMD, we also consider the photochemical and spectrophotometric features of the lipofuscin compounds responsible for generating the fluorescence emission.

No MeSH data available.


Related in: MedlinePlus