On the possibility of intensifying the photochemical stage of scleral collagen riboflavin/UV crosslinking by tissue optical clearing
The possibility of increasing the efficiency of riboflavin (RF)/ UV crosslinking (CXL) of sclera by using immersion optical clearing (IOC) of the tissue before UV treatment was investigated. The intensity of photochemical processes of RF/UV CXL was estimated by means of monitoring of the relative content of riboflavin in the tissue during the CXL process. The relative content of riboflavin at different depths in the tissue was estimated from the decay times of tissue fluorescence, which was measured using fluorescence lifetime imaging microscopy (FLIM). The measurements were conducted in vitro on specimens of porcine sclera. An 88% aqueous glycerol solution was used as the immersion clearing agent. It was found that optical clearing significantly increased the intensity of the photoinduced conversion of riboflavin into nonfluorescent forms in the tissue during UV exposure. In the case of CXL without IOC the residual riboflavin content in the tissue at the depths from 40 to 75 μm after UV treatment was measured to be approximately 5.6 times higher than in the case when IOC was used.
Saratov State University
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