Findings of an Interlaboratory Trial of the Enucleated Eye Method as an Alternative Eye Irritation Test

Abstract

The enucleated eye test (EET) for screening eye irritants was first described in 1981. In order to validate this method, an interlaboratory trial was established. Substances of varying degrees of ocular irritation were tested using both a 10 and a 60 s exposure period. The 10 s exposure time allowed the most irritant of substances to be identified by the EET. For the majority of substances tested, the 60 s exposure generated greater responses than the 10 s exposure. By assessing the in vitro response, each substance could be graded into one of four irritancy ratings. Despite the three laboratories adopting different in vitro grading systems, consistency amongst the laboratories was good, with 22 of the 27 substances tested being rated within one in vitro category. In comparison with existing in vivo data, the in vitro responses from a 10 s exposure correlated better than the reactions from a 60 s exposure protocol. The effects of liquid test substances were more successfully predicted in vitro than the effects of solid test substances.