Hjalmar Schiøtz, the great Norwegian innovator and his ophthalmoscope.

Recently, the authors encountered an intriguing and largely incomplete ophthalmoscope. The quest to identify and restore it led to a re-evaluation of the evolution of the modern-day ophthalmoscope and a re-examination of the life and contributions of its inventor, the Norwegian ophthalmologist Hjalmar August Schiøtz.

Hans Goldmann (1899-1991).

Hans Goldmann (1899-1991), born in Komotau in Bohemia, studied medicine in Prague. He was trained in physiology by A.V. Tchermak-Seysenegg and in ophthalmology by A. Elschnig in Prague and by A. Siegrist in Berne. He succeeded Siegrist as chairman of the Department of Ophthalmology in Berne in 1935. He was granted Swiss citizenship in 1936. For almost 70 years, Hans Goldmann has influenced, and continues to influence, the daily practice of ophthalmology. In 1933, he and W. Haag and H. Papritz produced the Haag-Streit-Slitlamp 320. This instrument, together with contact lenses that he developed, enabled the whole eye from the surface of the cornea to the fundus to be examined with the patient in the seated position. In 1945, the Goldmann Cupola-Perimeter followed, which allowed the standardization of background and target luminance. The applanation tonometer was introduced in 1954 and, in 1958, the Haag-Streit Slitlamp 900. The presentation of every new instrument was accompanied by a clinical article demonstrating its value. Goldmann's research culminated in the understanding of the production and outflow of the aqueous. He determined the volume of the anterior chamber in 1941, detected the aqueous veins in 1945, proved that these contain aqueous in 1949, measured aqueous production by fluorescein dilution curves in 1950, and coined the formula that determines outflow facility. This article is to remind the current generation of ophthalmologists of an outstanding man who developed our understanding of disease and who created the many of the instruments that still determine the daily practice of ophthalmology worldwide.

Application of physical principles in the development of tonometry.

A review of the development of applanation tonometry is undertaken from the perspective of the physical principles involved. Original articles that have contributed to this process are discussed. The result of this endeavour leads to a conclusion that corneal thinning procedures have no effect on original intraocular pressure. Also concluded is a methodology that would allow the direct measurement of original intraocular pressure.

[Hjalmar Schiötz and his tonometer]. / Hjalmar Schiøtz og hans tonometer.

Hjalmar August Schiøtz (1850-1927) was the first Norwegian professor of ophthalmology. Drawing on his rare technical skills and deep insight into advanced mathematics and physiological optics, he designed several ophthalmological instruments, the two most important being the ophthalmometer he designed together with Professor Javal in Paris in 1881 and his own tonometer in 1905. Throughout more than 50 years, the Schiøtz tonometer upheld its position as the instrument most widely used world-wide for measuring intraocular pressure.

The Utrecht Ophthalmic Hospital and the development of tonometry in the 19th century.

During the second half of the 19th century Donders, Snellen and co-workers of the Utrecht Eye Clinic played an important role in the development of clinical tonometry. These indefatigable researchers designed and built a number of tonometers of which most have been saved and which are now on display in a permanent exhibition in the Royal Netherlands Ophthalmic Hospital at Utrecht.