Evaluation of time-resolved autofluorescence images of the ocular fundus

Dietrich Schweitzer; Martin Hammer; Frank Schweitzer; Stefan Schenke; Elizabeth R Gaillard

doi:10.1117/12.499641

8 October 2003 Evaluation of time-resolved autofluorescence images of the ocular fundus

Dietrich Schweitzer, Martin Hammer, Frank Schweitzer, Stefan Schenke, Elizabeth R Gaillard

Proceedings Volume 5141, Diagnostic Optical Spectroscopy in Biomedicine II; (2003) https://doi.org/10.1117/12.499641
Event: European Conferences on Biomedical Optics 2003, 2003, Munich, Germany

Abstract

Changes in the metabolism can be assumed as a first sign of several ocular diseases. If such metabolic alterations are detectable, diseases might be treatable, before morphological alterations are manifest. The redox pairs of co-enzymes fluoresce after excitation and change their fluorescence properties depending on the oxidative state of cellular metabolism. Metabolic by-products and connective tissue exhibit also auto-fluorescence. The detection and discrimination of endogenous fluorophores at the fundus by selected excitation or evaluation of emission spectra is not possible with a high spatial resolution. The lifetime of electrons in the excited stage is also substance specific and is not influenced by the absorption spectra of non-fluorescent substances at the fundus. For that reason, a Laser Scanning Ophthalmoscope was developed for the 2-dimensional measurement of time - resolved auto-fluorescence at the living human eye-ground. In first studies, different changes in auto-fluorescence were found after respiration of oxygen between fundus sites. Between young and older persons as well as patients suffering from age-related macular degeneration different lifetime-ranges were detected from the same anatomical region. For comparison, lifetime measurements were performed on single substances. In a first step of interpretation, the frequency distribution of each lifetime in a region of interest can be compared between in vivo and in vitro measurements. Presenting the results in Tau 1-Tau 2 diagrams, specific clusters can be found in both types of measurement, covering each other partially and allowing interpretation of measurements from the living human eye.

Citation Download Citation

Dietrich Schweitzer, Martin Hammer, Frank Schweitzer, Stefan Schenke, and Elizabeth R Gaillard "Evaluation of time-resolved autofluorescence images of the ocular fundus", Proc. SPIE 5141, Diagnostic Optical Spectroscopy in Biomedicine II, (8 October 2003); https://doi.org/10.1117/12.499641

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