Abstract
PurposeWe investigated the autofluorescence (AF) signature of the microscopic features of retina with age-related macular degeneration (AMD) using 488 nm excitation.MethodsThe globes of four donors with AMD and four age-matched controls were embedded in paraffin and sectioned through the macula. Sections were excited using a 488 nm argon laser, and the AF emission was captured using a laser scanning confocal microscope (496–610 nm, 6 nm resolution). The data cubes were then analyzed to compare peak emission spectra between the AMD and the controls. Microscopic features, including individual lipofuscin and melanolipofuscin granules, Bruch’s Membrane, as well macroscopic features, were considered.ResultsOverall, the AMD eyes showed a trend of blue-shifted emission peaks compared with the controls. These differences were statistically significant when considering the emission of the combined RPE/Bruch’s Membrane across all the tissue cross-sections (p = 0.02).ConclusionsThe AF signatures of ex vivo AMD RPE/BrM show blue-shifted emission spectra (488 nm excitation) compared with the control tissue. The magnitude of these differences is small (~4 nm) and highlights the potential challenges of detecting these subtle spectral differences in vivo.
Highlights
[3] Photoreceptor loss is associated with changes in the complex system supporting their function, cause and effect remain a subject of great dispute. [4,5,6] This support system includes the retinal pigment epithelium (RPE), a monolayer of pigmented cells that exchange metabolites with the neighboring photoreceptor cells, and recycle chromophores critical to the visual cycle
Our goal is to study ex vivo the AF signatures of Bruch’s Membrane (BrM) and RPE and their relative contribution to the overall fundus autofluorescence (FAF) signature in eyes with dry Age-related macular degeneration (AMD) compared with control eyes
We take advantage of higher spectral resolution combined with least-squares regression analysis to improve the spectral sensitivity, and using a higher spatial resolution, we examine the spectral contribution of the different component fluorophores within the RPE to the overall RPE/BrM AF signature in AMD and control tissue
Summary
[3] Photoreceptor loss is associated with changes in the complex system supporting their function, cause and effect remain a subject of great dispute. The ability to follow certain aspects of these pathological changes in vivo has been enhanced by the development of fundus autofluorescence (FAF) imaging. Our goal is to study ex vivo the AF signatures of BrM and RPE and their relative contribution to the overall FAF signature in eyes with dry AMD compared with control eyes. We take advantage of higher spectral resolution combined with least-squares regression analysis to improve the spectral sensitivity, and using a higher spatial resolution, we examine the spectral contribution of the different component fluorophores within the RPE to the overall RPE/BrM AF signature in AMD and control tissue.
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