12 - Ocular Irritation

Abstract

This chapter discusses the use and limits of the Draize eye test, and describes the in vitro alternatives for it. The Draize rabbit's eye test has been used as the standardized animal assay for ocular safety assessment for more than 50 years. The scoring system of the Draize eye test allows assessment of the full spectrum of eye irritation properties of test materials, ranging from non-irritating to severely irritating and corrosive properties. Today, the Draize eye test is still the world-wide standard for assessing the ocular irritation of new chemicals. However, the Draize rabbit's eye test has been criticized more than any other toxicological test in animals by the animal welfare movement. Moreover, the test has also been criticized for two scientific reasons: on the one hand for the subjectivity of the method and on the other for over predicting the response in humans. It has been a great challenge so far to develop in vitro methods that are simple to perform and provide reproducible results which are sufficient for ocular risk assessment in humans. The chapter gives an outline of the most promising non-animal methods which are currently undergoing validation. Finally, the current use of in vitro alternatives for in-house safety testing and for regulatory purposes is discussed in the chapter.