Experimental research for the efficacy and cytotoxicity of methylene blue for anterior capsule staining

Abstract

Objective To investigate the efficacy and corneal endothelial cytotoxicity of methylene blue in rabbit anterior capsule staining during cataract surgery. Methods Concentrations of 0.1%, 0.2%, 0.5% and 1.0% methylene blue were used to stain rabbit lens in vivo for 10 seconds. The lowest staining concentration was evaluated and all the concentration's staining status was compared with 0.06% trypan blue. The effect of 10 seconds and longer exposure time of 30 seconds and 60 seconds with all the concentrations on endothelial cells were also investigated. Results 0.2% and its higher concentrations of methylene blue provided comparable contrast of staining for 10 to 60 seconds of exposure. Changes in corneal endothelial cells' morphology after staining had no statistic difference at any tested concentration. But methylene blue had an obvious cytotoxicity to corneal endothelial cells at the concentration of 1% and 0.5% with the exposure time for 60 seconds under light microscope and electron microscope. A slight cytotoxicity could be tested at the two concentrations with the exposure time for 30 seconds. Conclusions 0.2% Methylene blue can be used for optimal enhancement of anterior capsule visibility for capsulorhexis, within 60 seconds of exposure time it appears to be safe as determined by no cytotoxic effects on rabbit corneal endothelial cells in vivo. Key words: Methylene blue; Dyes; Lens anterior capsule staining; Continuous curvilinear capsulorhexis