Toxicity of Benzalkonium Chloride on Corneal Endothelium of Rabbits

ABSTRACT

An experimental study was performed on 16 rabbits to evaluate the toxicity of benzalkonium chloride(BAK) on the corneal endothelium. Each rabbit received two drops of 0.01% BAK in the right eye and BSS in the left eye as control. The rabbits were divided into 4 groups instillation of BAK 20 times at 6-minute intervals in normal cornea(group 1), instillation of BAK 40 times at 3-minute intervals in normal cornea (group 2), instillation of BAK 20 times at 6-minute intervals in de-epithelized condition with the size of 6mm diameter(group 3) and instillation of BAK 40 times at 3-minute intervals in deepithelized cornea(group 4). After the last instillation of BAK, histopathologic examination was performed with electron microscope. Group 1 showed nearly normal corneal endothelial findings, but group 2, 3 and 4 showed enlarged rough endoplasmic reticulum, partially distrupted Goigi apparatus and mitochodria, the presence of vacuoles and phagosomes. Group 4 showed severe destruction of subcellular structures. The results of this study indicate that an exaggerated use of topical drug containing 0.01% BAK may induce corneal endothelial damage, especially when the epithelium was already damaged.