Bovine corneal opacity and permeability test method

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. BCOP is an organotypic model that provides short-term maintenance of normal physiological and biochemical function of the bovine cornea in an isolated system. Damage by the test substance is assessed by quantitative measurements of changes in corneal opacity and permeability with an opacitometer and an ultraviolet/visible (UV/VIS) spectrophotometer, respectively. Both measurements are used to calculate an In Vitro Irritancy Score, which is used to assign an in vitro irritancy classification for prediction of the in vivo ocular irritation potential of a test substance. Although not part of the adopted OECD test guideline, histopathology can be useful to discriminate borderline cases (i.e., substances that produce results that preclude assignment to a single category) or to identify ocular damage that does not produce opacity or permeability changes in the isolated cornea. Histopathology can also be used where the mode of action cannot be easily predicted, when delayed effects might be anticipated, or when a more complete characterization of damage is needed