The Bovine Corneal Opacity and Permeability test method (BCOP) is an in vitro test method that can be used to identify chemicals (substances or mixtures) as either 1) causing “serious eye damage” (category 1 of the Globally Harmonised System for the Classification and Labelling of chemicals (GHS)), or 2) not requiring classification for eye irritation or serious eye damage according to the GHS.

The BCOP uses isolated corneas from the eyes of cattle slaughtered for commercial purposes, thus avoiding the use of laboratory animals. Each treatment group (test chemical, negative/positive controls) consists of a minimum of three eyes where the cornea has been excised and mounted to a holder. Depending on the physical nature and chemical characteristics of the test chemical, different methods can be used for its application since the critical factor is ensuring that the test chemical adequately covers the epithelial surface. Toxic effects to the cornea are measured as opacity and permeability, which when combined gives an Irritancy Score (IVIS or LIS, depending on the device) for each treatment group. A chemical that induces an IVIS ≥ 55.1, or an LIS>30 and OD₄₉₀ > 2.5, or LIS>30 and lux/7 > 145, is defined as a category 1 (“causing serious eye damage” according to the GHS); a chemical that induces an IVIS≤ 3 or an LIS≤ 30 is considered as not requiring classification for eye irritation or serious eye damage according to the GHS.