This Volume of the Documenta Ophthalmoligica Proceeding Series presents the scientific papers read during the 13th Congress of SIDUO, the International Society for Ultrasonic Diagnosis in Ophthalmology, held in Vienna in the Summer of 1990. It was the second time that SIDUO had selected Vienna as a site for its biennial congresses in the 28 years of its existence. Previously, the 3rd SIDUO Meeting had taken place as part of the 1st World Congress for Ultrasonic Diagnosis in Medicine organized by Karl C. Ossoinig in 1969. Ossoinig, the pioneer of Standardized Echography opened the scientific sessions of SIDUO 13 with the First Jules Fran | Ophthalmic Echography 13 by P. Till, Paperback | Indigo Chapters