Applications of the EYTEX method

The EYTEX method is an in vitro test to predict the ocular irritation of chemicals and formulations based on alterations in a protein matrix. Results of a multi-laboratory study of 130 samples have previously been published. Four independent studies were conducted to evaluate further the accuracy, reproducibility and applicability of the EYTEX method. This method was performed according to the previously published procedures. Dose-response curves were produced at concentrations of samples similar to those used in the Draize test. Spectrophotometric data were used to establish irritancy classifications, and an EYTEX/Draize equivalent was calculated. These studies included a wide range of chemicals and formulations with varying degrees of irritation and mechanisms of ocular toxicity. Nine hundred and twenty-one cosmetic, household, petroleum and agricultural products were analysed by the EYTEX method. Seven hundred and thirty-six EYTEX results were within one classification of the Draize result. The EYTEX results exhibited an overall substantial equivalence of 91% to the Draize results with a range of 89 to 93% depending on the particular product group. The inter-assay coefficient of variation was 8.1% and the intra-assay coefficient of variation was 10.7%. These studies indicate that the EYTEX method exhibits a high correlation with the Draize test for the four diverse product groups studied and validates the predictive potential of the EYTEX method as an in vitro screen for ocular irritation.