The effects of carbocaine hydrochloride on isolated porcine corneas in vitro: a comparison of opacity, hydration and thickness

By Igarashi, H. - Sato, C. - Ogawa, K. - Kojima, M. - Chiba, Y.

Several concentrations of carbocaine hydrochloride, a local anaesthetic, were applied to isolated porcine corneas and stromas for periods of 1, 2, 3 and 4 hours. Increases in opacity (manifested as decreases in the intensity of a beam of light passed through the cornea from the epithelium to the endothelium), hydration (determined by the loss of water on drying to constant weight), and thickness (measured with a micrometer screw gauge) were determined. Small, time-related increases in opacity, associated with increases in hydration and thickness, were observed in control preparations and in preparations treated with 0.5-2% carbocaine hydrochloride over a 4-hour incubation period. However, only those increases resulting from incubation for 4 hours with 2% carbocaine hydrochloride differed significantly from control values. Higher concentrations (3% and 16%) also caused opacity, but decreased hydration and thickness, probably because of the hypertonicity of these solutions.