[The adverse effects of local anesthetics on the eye in the development of ocular irritation test]

Referring to the ocular damage produced by local anaesthetics applied to the eye, the authors suggest the use of a test, to reveal the danger that some ophthalmic preparations may represent for patients. They review the studies devoted to the evaluation of ocular damage, particularly those which resulted into tests based on the methodology of Draize. A test scaled down to the mouse eye is described, in which the subjective appreciation is completed by an objective measurement. The test is based on the increased permeability of injured cornea for fluorescein. The fluorescence emitted by this tracer depends on the extent of the micro-lesions and is measured with an optical electronic device. The possibilities and limitations of this test are determined by the relationship between dose and extent of ocular damage. Such a relationship has been established for oxybuprocain. An appropriate concentration of this local anaesthetic allows to investigate the influence of adjuvants, preservatives and viscosifiers on the effect of oxybuprocain on the cornea. The authors conclude that it is possible to apply this test to the development of well-tolerated ophthalmic preparations.