gms | German Medical Science

7th International Symposium on AMD: Age-related Macular Degeneration – Understanding Pathogenetic Mechanisms of Disease

20.09. - 21.09.2019, Baden-Baden

Clinicopathologic comparison of fluorescence lifetimes and spectral characteristics in AMD

Meeting Abstract

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  • Martin Hammer - Jena/D
  • R. Schultz - Jena/D
  • D. Meller - Jena/D

7th International Symposium on AMD: Age-related Macular Degeneration - Understanding Pathogenetic Mechanisms of Disease. Baden-Baden, 20.-21.09.2019. Düsseldorf: German Medical Science GMS Publishing House; 2020. Doc19amd48

doi: 10.3205/19amd48, urn:nbn:de:0183-19amd486

Veröffentlicht: 5. Februar 2020

© 2020 Hammer et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

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Goal: to study fluorescence lifetimes of RPE/retina and drusen in vivo and compare with post-mortem donor tissue measurements.

Methods: 43 patients (mean age: 74.1±7.9 years) with non-exudative AMD and no geographic atrophy were included. Fundus AF from a 30° retinal field was investigated with the Heidelberg Engineering fluorescence lifetime imaging ophthalmoscope (FLIO) in a long- (LSC) and a short-wavelength channel (SSC). Mean fluorescence lifetimes tm were measured. Spectral ratio (sr) of both fluorescence channels was calculated as well. Two-photon microscopy was used to study unstained histological slices from 9 post-mortem donor eyes. Fluorescence lifetimes as well as spectra were recorded.

Results: 2760 individual soft drusen were identified in vivo. There was no significant difference in tm between the drusen and the unaffected fundus (SSC: 284±54ps vs. 280±57ps; LSC: 337±34ps vs. 334±40 ps), however, the sr was significantly higher in drusen (0.555±0.077 vs. 0.539±0.081, p<0.0005). On average, hyperfluorescent drusen showed longer tm than surrounding unaffected fundus (SSC: 17.9±41.9ps, p=0.074, LSC: 16.3±29.1ps, p=0.02, N=41) although most of them were not discriminable by lifetime. This difference was significantly more pronounced in small, demarcated drusen than in diffuse ones (SSC: 22.9±27.5ps vs. -2.8±20.6ps, p=0.003, LSC: 27.1±29.3ps vs. 3.0±25.7ps, p<0.0005). In histology, 171 drusen were identified. They showed considerably longer lifetimes than the RPE: (SSC: 596±201ps vs. 179±36ps, LSC: 549±153ps vs. 286±37ps, p<0.0005) and the peak emission wavelength was green-shifted as well.

Conclusions: Whereas RPE fluorescence is dominated by Lipofuscin, drusen contain other fluorophores as is evident from their different fluorescence characteristics. This is much more obvious in histology than in the in vivo situation where drusen are hidden underneath the RPE. Nevertheless, in vivo spectral and lifetime characteristics of fluorescence by FLIO revealed differences of retinal/RPE and drusen fluorescence as well as the variability of drusen fluorescence which might have clinical impact.