Comparison of two human cell-based in vitro eye hazard assessment methods: the cytotoxicity test for evaluation of eye irritation (CEI) and the OECD 492B method.

Lately, we have developed a cytotoxicity test for evaluation of eye irritation (CEI), which is able to classify a substance as serious eye damage, eye irritant or not requiring classification. The OECD 492B method can also classify substances into three categories. The aim of the present study was to compare two methods for classifying chemicals into eye hazard categories: OECD 492B and CEI. The first was performed according to the OECD 492B guideline on SkinEthic human corneal epithelium and the second according to our internal protocol on the HDFn cell line. Eighteen substances were tested (applied neat or at 20% concentration in OECD 492B and at the following concentrations in CEI: 250 mg/mL, 50 mg/mL, 15.8 mg/mL, 5 mg/mL, 1.6 mg/mL, 0.5 mg/mL). The methods were compared using statistical and descriptive analysis. Based on a limited number of chemicals, for all eye hazard categories, the performance indicators (e.g. accuracy, sensitivity and specificity) of the OECD 492B method were the same as or higher than those of the CEI method. However, the CEI method is considered to be more economical. Because the dataset was limited (18 substances), these results should be considered preliminary.