Purpose
Fluorescent lifetime imaging ophthalmoscopy (FLIO) is a new imaging method that allows measurements of fluorescence lifetimes in vivo in the retina. In contrast to fundus autofluorescence where fluorescence intensities are measured, FLIO measures the decay time of natural fluorophores which is in the range of picoseconds (ps). We have recently established a mouse model of experimental vein occlusion. We describe here the fluorescence lifetime features in experimental vein occlusion.
Methods
Retinal vein occlusion was induced in 7 BALB/c mice in the superior vein using indirect la-ser photocoagulation. The retina was imaged at day 3 with the fluorescence lifetime imaging oph-thalmoscope. In addition fluorescein angiograms, color fundus photographs and optical coherence tomograms were obtained to verify the success of retinal vein occlusion.
Results
Fluorescence lifetime imaging was feasible in all mice and showed characteristic and highly reproducible changes in the area affected by retinal vein occlusion at day 3. Average fluorescence lifetimes in the retinal areas affected by experimental vein occlusion were significantly (831ps versus 1014ps, p<0.005) shorter when compared to healthy retina. Fluorescence lifetime analysis of the area of laser treatment was not significantly different from healthy retina (1026ps versus 1014ps).
Conclusions
We were able to show that fluorescence lifetimes are altered in the retina after experimental vein occlusion. The combination of the clinically highly relevant vein occlusion model and the fluorescence lifetime imaging technique may help to develop a better understanding of this disease and may be useful for drug development.
Keywords: 551 imaging/image analysis: non-clinical •
688 retina •
749 vascular occlusion/vascular occlusive disease