Effects of intracameral lidocaine on ocular tissues

Purpose: To investigate the ultrastructural changes in iris and corneal tissue induced by intracameral 1% lidocaine infusion applied during lens extraction in a rabbit model. Methods: The study was conducted using New Zealand rabbits. Eight rabbits received 0.2 mL 1% lidocaine hydrochloride intracamerally and lens extraction was performed, keeping the posterior capsule intact. After lens extraction, cornea and iris tissue samples were obtained for electron microscopy. Eight eyes were included as a control group. Results: Electron microscopy revealed morphological abnor-malities in both cornea and iris of the lidocaine injected eyes, different from the control group. Cytoplasmic vacuolization, phagosomes and residual bodies were observed in epithelial cells. Corneal fibroblasts contained fluid-filled vacuoles, which could be due to the influx of water into the cells as a result of corneal endothelial damage. Mitochondrial swelling and residual bodies were also seen in the cytoplasm of fibroblasts. Blood vessels in the iris contained fluid material composed of fibrin and proteinaceous material and many vacuoles showed vascular endothelial injury. Conclusion: Even a short period of exposure of intra-cameral lidocaine to the ocular tissues can induce histo-logical changes that may result in functional defects.