The use of low-volume dosing in the eye irritation test

Abstract

The Draize rabbit eye test was developed to provide a method for assessing the irritation potential of materials that might come in contact with human eyes. The method involves the instillation of 0.1 ml of a test liquid (100 mg solid) into the conjunctival sac of an animal's eye. A refinement of the Draize test is the low-volume eye test in which 0.01 ml of a substance is placed directly on the cornea of the eye. Studies indicate that the low-volume method provides a better correlation to human eye irritation experience for some substances. The Interagency Regulatory Alternatives Group (IRAG) proposes that the low-volume eye test can be used to substantiate the irritancy of suspect severe ocular irritants that have not been eliminated by various pre-eye test 'screens'. A substance testing positive by the low-volume method can be classified as an irritant; one that tests negative will require further testing by the use of the 0.1-ml volume procedure. For all other definitive testing, the Draize test (0.1 ml) should be used. Results from a questionnaire distributed at the IRAG workshop showed that many workshop participants thought that the low-volume test should be used as an eye irritation screening procedure.