Minister, Mr. Mayor, Mr. Honourary President, Honoured guests, Ladies and gentlemen, Dear colleagues and friends: On behalf of the Ophthalmological Society of the German Democratic Republic I welcome you to this symposium. I am glad to see so many experts from more than 20 countries of all parts of the world assembled here in Schwerin, who have travelled far and overcome many obstacles in doing so. I wish to extend a special welcome to the Vice-Minister of Health of the GDR, whom we should like to thank for the continuing generous support of the government of the GDR for this event. It is a great pleasure to welcome scientists from socialist countries such as the Soviet union, Poland, Cechoslovakia, Hungary, Bulgaria and Yugoslavia and from non socialist countries such as USA, Canada, Great Britain, The Netherlands, Belgium, France, Federal Republic of Germany, Austria, Sweden, Finland, Denmark, Italy, Spain, Switzerland and far away Japan and Australia. I have the great honour to welcome Prof. FRANQOIS as our Honourary President, our scientific directors Prof. VOLKOV from Leningrad and Prof. BLODI from Iowa City, and Dr. ZIMMERMAN and other members of the Verhoeff Society, and Prof. GAILLOUD and Prof. MEYER-SCHWIcKERATH as prominent representatives of the Club Jules Gonin. We are delighted that you have accepted our invitation.

We in ophthalmology are fortunate to be able to measure quantitatively many aspects of ocular morphology and visual function. These measurements are either objective (e. g. electroretinography, tonometry, electromyography, visually evoked responses, etc.) or subjective and psychophysical (e. g. visual acuity, visual fields, color vision, etc.). One aspect of corneal physiology and pathology which has so far escaped careful and reliable measurements is corneal sensitivity. Previous attempts have been rather crude and can be compared to measuring intraocular pressure by digital compression. Professor Draeger has for the last decade and a half directed his attention to the question of esthesiometry of the cornea. He has a gift for constructing and devising new ingenious ocular instruments. His handheld tonometer is a splendid example. He has now applied the principle of this instrument to the new electronic optical esthesiometer. In many publications he has reported on his first results using this modern technique to study corneal physiology and evaluate certain pathologic conditions. In this monograph Professor Draeger has collected all of his material and reports on his long experience. The usefulness of this instrument is just beginning to be appreciated. It is obvious that this new measuring device will help us in the fitting of contact lenses, evaluating herpes simplex infections of the cornea, follow the postoperative course of patients with a penetrating keratoplasty, etc.

This monograph by Professor Alexandridis continues the proud tradition of German ophthalmology in its discussion of the pupil and its importance in the diagnosis of ocular, neurologic, and systemic diseases. The first encyclopedic work on the pupil was written by Wilbrand and Saenger at the end of the 19th century. This redoubtable pair of physicians collected, analyzed, and clas sified all the material available at that time, bringing order into the previous chaos. The second major work was the book by C. v. Behr shortly after World War 1. At that time, syphilis had been accurately diagnosed with the aid of serologic tests, and pharmacologic effects on the pupil had become well known. The third significant development was initiated before World War II by the neurologist Otto Lowenstein, whose work was later brilliantly continued by his pupil and niece Irene Lowenfeld. The introduction of their clinically useful pupillograph made quantitative analysis possible. There followed a number of important contributions to the knowledge of pupillary physiology and pathology, espe cially by Harms in Tiibingen and Thompson in Iowa City. But the next decisive contribution is this monograph by Alexandridis."