Effect of intracameral anesthesia on the corneal endothelium

Purpose: To evaluate the effects of intracameral anesthesia on the corneal endothelium. Setting: Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Japan. Methods: This study comprised 24 eyes of 12 white rabbits. One eye of 3 rabbits each was injected with preservative-free lidocaine at concentrations of 0.02, 0.2, or 2% fellow eye injected with balanced salt solution (BSS(R)) as a control. The anesthetic agent was injected into the anterior chamber using a bimanual technique. Immediately after enucleation, the cornea was examined by scanning electron microscopy. Results: Scanning electron microscopy revealed no abnormal findings in the eyes injected with lidocaine 0.02 or 0.2% when compared with eyes in the control group. Scanning electron microscopy of the eyes injected with lidocaine 2% showed irregular hexagonal endothelial cells and a significant loss of microvilli. Conclusion: Intracameral anesthesia with high concentrations of lidocaine risks corneal endothelial damage but at the low concentration usually used in cataract surgery did not appear to have an adverse effect.