A test for crystalline lens biocompatibility

The current use of monkeys for testing intraocular fluids and viscoelastic materials is being questioned because of the decreasing availability and increasing cost of these scarce animals. The rabbit is an inexpensive, readily available, and convenient animal which might provide an alternative model for this purpose. In this study we have outlined the lens changes (clefts or vacuoles) that are observed in the New Zealand white rabbit as a result of toxicity to intraocular test materials. We used two viscoelastic agents, 1% sodium hyaluronate-Healon and 2% carboxymethylcellulose, and balanced salt solution to evaluate the efficacy and reproducibility of lens changes in this test study. The lens changes in each case were reproducible and could easily be graded. When used in concert with other tests, this new test can help in the preliminary evaluation of an ophthalmic material before its final clinical use in humans.