Eye Irritation. In Vitro Screening Techniques of Eye Irritation

Assessment of ocular irritancy is a necessary step in the safety evaluation of both cosmetic ingredients as well as products. Since eye irritation testing of cosmetics in vivo is no more possible in the EU, and since there is no single in vitro testing method available that could address this endpoint, the eye irritation testing in vitro is conducted as battery of tests followed by deep analysis of all available data. 

Following test methods are mostly forming such a testing battery: BCOP (Bovine Corneal Opacity and Permeability), ICE (Isolated Chicken Eye) and/or STE (Short Term Exposure) to distinguish Category 1 chemicals (severely irritating materials). EpiOcular EIT (EpiOcular Eye Irritation Test) can be used fo distinguish between materials that do not require classification “Not classified” versus “classified” (Category 1/ Category 2). To distinguish between Category 1 and Category 2, the following methods are relevant, but not fully regulatory accepted: histopathology in association with the BCOP and ICE, EpiOcular ET-50 (EpiOcular time-to-toxicity test), SMI (Slug Mucosal Irritation).

In order to use correct testing strategy, it is important to consider the pH, QSAR, possible drivers for classification (such as corneal opacity, iritis, conjunctival redness, conjunctival chemosis, days to clear and/or persistence of effects) and combine this information with the information on applicability domain and strengths and limitations of each the method.

The presentation will provide an overview of test methods applicable for the assessment of ocular irritation in vitro and will discuss testing strategies that could be used to correctly predict the eye irritation potential of cosmetics. 

Dr. Helena KandarovaSlovak Republic