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Decreased riboflavin impregnation time does not increase the risk for endothelial phototoxicity during corneal cross-linking

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First Author: J.Brekelmans THE NETHERLANDS

Co Author(s):    A. Marcovich   A. Brandis   M. Dickman   R. Nuijts   A. Scherz        

Abstract Details

Purpose:

To evaluate the Riboflavin (RF) concentration and distribution in the corneal stroma and the risk for endothelial photodamage during corneal crosslinking (CXL) following 10- and 30 minutes impregnation.

Setting:

In vitro, and ex vivo and in vivo animal study, Weizmann Institute of Science, Israel

Methods:

De-epithelialized rabbit corneas were subjected to impregnation for 10 and 30 minutes with different RF formulations. Human corneal endothelial cells (HCEC) were subjected to different RF concentrations and Ultra violet A (UVA) dosages. Assays included fluorescence imaging, absorption spectroscopy of corneal buttons and anterior chamber humor, and cell viability staining.

Results:

After 10- and 30-minutes of impregnation respectively, anterior chamber fluid showed a RF concentration of (1.6±0.21)•10-4% and (5.4±0.21)•10-4%, and trans-corneal absorption reported an average corneal RF concentration of 0.0266% and 0.0345%. This results in a decrease in endothelial RF concentration from 0.019% to 0.0056%, while endothelial UVA irradiance increases by 1.3-fold, when changing from 30- to 10 minutes of impregnation. HCEC cell viability in cultures exposed to UVA illumination and RF concentrations as concluded for the endothelium after 10- and 30 minutes impregnation was non-statistically different at 51.0%±3.9 and 41.3±5.0%, respectively.

Conclusions:

The risk for endothelial damage in CXL by RF/UVA treatment does not increase by shortened impregnation because the 30% increase in light intensity is accompanied by a 3.4 fold decrease of the RF concentration in the posterior stroma. This is substantiated by similar endothelial cell toxicity seen in vitro, that in fact appears to favor 10-minutes impregnation.

Financial Disclosure:

... gains financially from competing product or procedure