A more realistic animal technique for predicting human eye response

Abstract

The FHSA test (CPSC, 1981) for eye irritation in rabbits overpredicts the likely response of the human eye. Nineteen different chemicals, mixtures or solutions that had different degrees of recognized irritancy potential to the human eye were tested in albino rabbit eyes at dose volumes of 0.003, 0.01, 0.03 and 0.1 ml. The material was administered directly onto the rabbit cornea, without forced closing of the eyelid and without rinsing. A dose volume of 0.01 ml most often gave results that were consistent with information on effects of human eye exposures. The report of this work (Griffith et al. Toxic. appl. Pharmac. 1980, 55, 501) recommended that this more realistic ‘low-volume’ technique (0.01 ml of test material) should replace the FHSA test (0.1 ml of test material). The recovery times of human eyes after accidental exposure to consumer products in the USA, either during manufacture or in incidents involving consumers, were compared with the number of days-to-clear of rabbit eyes (tested in either the FHSA or the low-volume test) or monkey eyes exposed to the same products. Over 500 incidents involving human eyes (over several years) are included in the review. All three animal techniques are shown to overestimate the severity of the human eye response, the FHSA method being the worst in this respect. Only the results of the low-volume rabbit test show a statistically significant correlation ( P < 0.05, r > 0.5) with human experience. It is recommended that this low-volume test in rabbits should replace the FHSA test as the internationally agreed test for eye-irritancy potential because it correlates best with the response of the human eye.