Evaluation of the bovine corneal opacity-permeability assay as an in vitro alternative to the Draize eye irritation test.

The bovine corneal opacity-permeability assay (BCO-P) was evaluated as an in vitro alternative test model for the Draize eye irritancy test. Fifty pharmaceutical and commercially available compounds were tested in the BCO-P assay. The compounds were selected on the basis of their in vivo irritancy potential as determined in previous Draize tests. Liquids as well as solids were tested. Corneal opacity and permeability were measured to determine ocular irritation potential. When two irritancy classifications (non-irritant and irritant) were considered, 96% of the tested chemicals were classified correctly. A 72% concordance was obtained when four irritancy classifications (non-irritant, mild, moderate and severe irritant) were considered. Furthermore, all compounds that were severe eye irritants in vivo were equally scored in vitro. The results of this study show that the BCO-P assay is a competent in vitro test system for the prediction of ocular irritation of chemicals. This test model can be used as a first screen to avoid in vivo testing of severe ocular irritants.