Two tiered approaches combining alternative test methods and minimizing the use of reconstructed human cornea-like epithelium tests for the evaluation of eye irritation potency of test chemicals.

In order to overcome the limitations of single in vitro eye irritation tests, Integrated Approaches to Testing Assessment strategies have been suggested for evaluating eye irritation. This study developed two tiered approaches combining alternative test methods. They were designed in consideration of the solubility property of test chemicals and to use the RhCE tests at final steps. The tiered approach A is composed of the STE, BCOP, HET-CAM or RhCE tests, whereas the tiered approach B is designed to perform simultaneously two in vitro test methods at the first stage and the RhCE test at the final stage. The predictive capacity of the two tiered approaches was estimated using 47 chemicals. The accuracy, sensitivity, and specificity value of the tiered approach A were 95.7% (45/47), 100% (34/34), and 84.6% (11/13), respectively, whereas those of the tiered approach B were 95.7% (45/47), 97.1% (33/34), and 92.3% (12/13), respectively. The approach A and B were considered to be available methods for distinguishing test chemicals of Category 1 (all 73.3%) and No Category (84.6% and 92.3%), respectively. Especially, the approach B was considered as an efficient method as the Bottom-Up approach, because it predicted correctly test chemicals classified as No Category.