Evaluation of the EYTEX system as a screening method for the ocular irritancy of chemical products

By Regnier, J.F. - Imbert, C. - Boutonnet, J.C.

The EYTEX method is an in vitro test used to predict ocular irritation, based on alterations in a protein matrix. We have evaluated this method with the aim of using it to screen chemicals. One hundred and forty-two products (commodities and specialities), having a wide range of chemical properties and ocular irritation potential in the rabbit, were tested with either the standard, MPA, AMA, RMA or UMA protocols. The results were compared with in vivo data obtained previously for each chemical and with the EEC labelling of eye irritation for dangerous substances. Intralaboratory repeatability and interlaboratory reproducibility were evaluated with seven other laboratories. Ninety-three per cent of the chemicals tested were qualified with the EYTEX method. The coefficients of the linear correlation between the EYTEX score and the maximal Draize score on the one hand and the maximal corneal score on the other hand, were 0.69 and 0.65, respectively. Compared to the EEC classification, the labelling of dangerous substances and for the prediction of severe irritants, sensitivity, specificity and equivalence were 94%, 89% and 78%, respectively. We observed nine false positives (22%) and two false negatives (2%) for the identification of R41-, R34- and R35-labelled products. The predictive values, for identifying R41, R34 and R35 products and non-irritants or R36 products were 78% and 97%, respectively. Repeatability (6.3) and reproducibility (8.9) were quite satisfactory. The EYTEX system exhibits the characteristics of a good screening method compatibility with a large range of chemicals; a simple and rapid procedure; good intralaboratory and interlaboratory reproducibility; cost effectiveness; high sensitivity, specificity and predictive value; and a low incidence of false negative and false positive results. Based on these results, we consider the EYTEX method to be a valuable tool for the screening of eye irritancy.