Aerobic responses of the cornea to isopropyl alcohol, measured in vivo

Abstract

With the use of a micropolarographic system, the effects of a series of isopropyl alcohol concentrations on oxygen uptake by the corneal epithelium of the rabbit were measured in vivo. Based on an exposure period of 10 sec, followed by a saline rinse, concentrations of greater than 31% were found to cause an abrupt and severe decline in oxygen uptake, with oxygen flux responses associated with 44% and greater being indistinguishable 60 min later from those of an epithelially denuded cornea. Initial flux variations, e.g. a mild depression at 24% and a mild elevation at just under 31%, were still evident 1 h following exposure. A slope model for estimating that concentration, the aerobic reduction dosage, which would reduce the oxygen flux activity of the epithelium to half, called here the ARD50, was found for this exposure time to be 37%. That estimate is in very close agreement with measured responses. A susceptibility ratio (SR), for comparing the relative toxicities of different agents based on the quotient of their ARD50 values, was calculated here for sodium hydroxide and isopropyl alcohol, and found to be 50:1.