Ocular fundus autofluorescence (FAF) imaging is widely used in ophthalmic diagnostics, specifically for age-related macular degeneration (AMD) diagnostics, a pathogenic modification reducing eyesight and eventually resulting in blindness. The major fluorescent structure is the retinal pigment epithelium (RPE). These cells contain fluorescent granules of different type with presumably different fluorophores. The granule composition in AMD RPE deviates from normal aged RPE. FAF with fluorescence lifetime and spectral resolution revealed specific changes in compromised, stressed, degenerating, and RPE cells. As such RPE changes indicate early AMD as well as disease progression. Fluorescence lifetimes and spectra are sensitive diagnostic markers provided by clinical fluorescence lifetime imaging ophthalmoscopy (FLIO). However, the mechanisms behind the change of fluorescence properties are not fully understood yet. This is a clear limitation for the interpretation of FLIO data.

The project HiResi4RPE is a collaboration of the BioPOLIM team in the Department of Microscopy at the Leibniz IPHT and the Institute of Physical Chemistry at the FSU with the Experimental Ophthalmology group at the UKJ. Significant contributions to a deeper understanding of pathogenic changes in AMD as well as to the interpretation of relevant FLIO data are expected from the combination of high-resolution fluorescence imaging of the RPE layer and of isolated RPE organelles with their chemical characterization by means of high-resolution infrared spectroscopic photo-induced force microscopy.

 Funded by the German Research Foundation under the project number 542825796