The 12th Congress of SIDUO took place in Iguazu Falls, Argentina, where participants could enjoy the scenery of the magnificent Falls. The organization was sponsored by the University Department of Oph­ thalmology, Buenos Aires; the University Department of Ophthalmology, EI Salvador; SAUMB (Socieded Argentina de Ultrasonografia en Medecina y Biologia) and CLEO (Club Latinoamericano de Ecografia OftalmoI6gica). The Honorary President was Professor Horacio Soriano from Buenos Aires. The local organizing committee consisted of the following persons: President Roberto Sampaolesi Vice President Atilio Lombardi Scientific Secretary: Eduardo Mayorga Treasurers Guillermo Iribarren Abelardo Cavatorta We are particularly grateful to Doctor J S Hillmann, Professor K C Ossoinig and Doctor nvf Thijssen, who have helped with their counsel and advice. I would also like to thank our congress secretaries Graciela Massonat and Cristina Taegl for their enormous help in organizing SIDUO XII. To Doctor Javier Cassiraghi and Doctor Walter de Gregory our thanks for their outstanding help in organizing the scientific sessions. Thanks are due to the commercial exhibitors and most of all to our sponsors: Laboratorios Pfoertner Cornealent and Biophysic Medical. Our special thanks to Doctor Tomas Pfoertner for his great administrative expertise and counsel and to Christine Warren from Biophysic for her help in financing these proceedings. The 12th SIDUO thanks for their generous support: Pupilent Plastic Lens Argentina, Grafica SA and Laboratorio Optico Santamarina.