Cytotoxicity of ophthalmic preservatives

Abstract

Light microscopy, flat preparation of the corneal endothelium, and scanning electron microscopy were used to evaluate the cytotoxic effect of three ophthalmic preservatives -benzalkonium chloride, chlorobutanol, and thimerosal. Only benzalkonium chloride caused significant damage to all the cellular components of the rabbit corneas including the endothelium. The dissimilarities in absorption may explain the cytotoxic effect of benzalkonium chloride and the lack of significant cytotoxicity of chlorobutanol and thimerosal. Whether or not one preservative is superior or preferable to another cannot be completely determined on the basis of this study. However, some of the limitations of chlorobutanol and thimerosal should be reconsidered on the basis of the cytotoxic effect of benzalkonium chloride. © 1974.