This volume represents the proceedings of the Fifth Congress of the International Society of Ocular Toxicology (ISOT), which was held at the Grove Park Inn and Resort in Asheville, North Carolina, October 13-17, 1996. We are delighted to present this volume to the ophthalmic community, especially those with a significant interest in ocular toxicol ogy. The Fifth Congress was developed around themes relating to ocular drug metabolism, the ocular pathophysiological effects of nitric oxide, government issues relating to the use of alternative methods for toxicity testing, and a workshop that encompassed comparisons of both in vitro versus in vivo models as well as different animal models. The outcome of this congress, embodied in this volume, is a contribution to the methodologies currently employed or under development and to various drug or physical effects on different ocular tissues. While the focus of this proceedings is on ocular effects of drugs or other materials, many of the contributions deal with topics that have a much broader interest. The workshop concerning the use of different model systems and the choice of the best animal model for drug testing covers a wide range of interests that ex tends far beyond specific ocular effects. This is especially true in the area of alternative methods and in the choice of the best animal model for examination of different disease entities.

This volume represents the proceedings of the Fifth Congress of the International Society of Ocular Toxicology (ISOT), which was held at the Grove Park Inn and Resort in Asheville, North Carolina, October 13-17, 1996. We are delighted to present this volume to the ophthalmic community, especially those with a significant interest in ocular toxicol ogy. The Fifth Congress was developed around themes relating to ocular drug metabolism, the ocular pathophysiological effects of nitric oxide, government issues relating to the use of alternative methods for toxicity testing, and a workshop that encompassed comparisons of both in vitro versus in vivo models as well as different animal models. The outcome of this congress, embodied in this volume, is a contribution to the methodologies currently employed or under development and to various drug or physical effects on different ocular tissues. While the focus of this proceedings is on ocular effects of drugs or other materials, many of the contributions deal with topics that have a much broader interest. The workshop concerning the use of different model systems and the choice of the best animal model for drug testing covers a wide range of interests that ex tends far beyond specific ocular effects. This is especially true in the area of alternative methods and in the choice of the best animal model for examination of different disease entities.

On behalf of the editorial board and the organizing committee of the 4th congress of the International Society of Ocular Toxicology (I SOT), held in AnnecyNeyrier du Lac, France, October 9 -13, 1994, we are pleased to present to the ocular toxicology community this indexed volume of our congress proceedings. The 4th congress was designed primarily to facilitate and update the knowledge in ocular electrophysiology and ocular pharmacokinetics, in both the clinical and preclinical aspects. The outcome of this 4th congress, established in this volume, is a useful contribution to the meth odology in both fields and will hopefully assist in the evaluation and interpretation of ocular findings recorded in animal studies on drugs and other chemicals, in order to protect human health. Undoubtedly, work on the mechanisms of ocular toxicology in the process of pharmaceutical development must continue and these proceedings, embodying the presented papers, will add to the data base. The editors, the congress organizing committee and the members of the International Society of Ocular Toxicology thank the speakers who gave their time, knowledge, and expertise to assist us in this project. The following manuscripts contain the main substance of each of the platform presentations and, in some cases, much more. Moreover, our thanks go to all the participants coming from a range of background- regulatory, academic and industrial -for their attention and excellent contributions during the discussion."