Viscoelastic Substances

O. HOCKWIN Just as Professor Hoffmann, the Chairman of the symposium on "Vis coelastic Substances", I should like to bid all participants a cordial wel come and thank you for your support in coming here. I should like to emphasize that it is your presence that is one of the most important pre requisites of this symposium, namely to form an expert forum in which clinical and experimental ophthalmology, the pharmaceutical industry and the authorities concerned with health and drugs from various states are represented. The subject matter can be dealt with from various points of view. I sincerely hope that everyone will make full use of this opportu nity of exchanging expert opinions. There will be an excellent chance of doing so in particular in the round-table conversation after lunch. I especially wish to thank all lecturers for their willingness to present the facts arising from their comprehensive knowledge and great experi ence which, after all, are necessary in respect of the classification of vis coelastic substances as therapeuticals on the one hand or medical devices on the other, and also to present these with expertise and to advise on the matter and to furnish a concluding commentary or recommendations. On the basis of examples of use in ophthalmology on which we will be informed in the morning session, we must firstly pay increased atten tion to the properties of the viscoelastic substances.