1 November 2004 In vivo measurement of time-resolved autofluorescence at the human fundus
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Abstract
An experimental setup for measurement of time-resolved autofluorescence of the human eye fundus is demonstrated. The method combines laser scanning technique and time-correlated single photon counting. The light source is a laser diode, delivering pulses of about 100 ps duration at a repetition rate of 40 MHz. The excitation wavelength is 446 nm and the cutoff wavelength of fluorescence detection is at 475 nm. The autofluorescence can be determined with a spatial resolution of 80×80 μm2 and 25 ps time resolution. The fluorescence decay is optimally approximated by a biexponential model. The dominating lifetime τ1 is shortest in the macula (320 to 380 ps) and reaches 1500 ps in the optic disk. The lifetime τ2 varies between 2 ns and 5 ns, but the spatial distribution is more homogeneous. Respiration of 100% oxygen for 6 min leads to changes in the fluorescence lifetime pointing to detection of coenzymes. Diagrams of lifetime τ2 versus τ1 are well suited for comparison of substances. Such lifetime clusters of a 20 deg macular field of a young healthy subject and of a patient suffering from dry age-related macular degeneration overlap only partially with τ2-τ1 clusters of lipofuscin.
© (2004) Society of Photo-Optical Instrumentation Engineers (SPIE)
Dietrich Schweitzer, Dietrich Schweitzer, Martin Hammer, Martin Hammer, Frank Schweitzer, Frank Schweitzer, Roswitha Anders, Roswitha Anders, Torsten Doebbecke, Torsten Doebbecke, Stefan Schenke, Stefan Schenke, E. R. Gaillard, E. R. Gaillard, Elizabeth R. Gaillard, Elizabeth R. Gaillard, } "In vivo measurement of time-resolved autofluorescence at the human fundus," Journal of Biomedical Optics 9(6), (1 November 2004). https://doi.org/10.1117/1.1806833 . Submission:
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