Epithelial healing: quantitative monitoring of the cornea following alkali burn

A micropolarographic system was used as a quantitative means of monitoring the healing course of corneal epithelium following a 10 second exposure to 0.20 N sodium hydroxide solution. Concentrations of less than that strength produced inconsistent flux baselines due to incomplete damage to the epithelium, while higher concentrations commonly involved the stroma as well. Virtually complete epithelial destruction (down to the basement membrane) and reproducible flux baselines were found, however, with the 0.20 N induced lesion studied in detail here. The healing course following those exposures consisted of two well defined phases: an initial period of hypoflux lasting some 48 h before rising back up to the pre-lesion baseline, followed then by a period of hyperflux lasting about 7 days before decreasing once again down to the pre-lesion baseline. This oxygen flux sequence closely parallels certain sliding and mitotic phases of epithelial healing already established in the literature.