Description

Schiøtz Tonometer

Schiøtz Tonometer by Professor Hjalmar Schiøtz. He was the first Director of the Eye Department at the Rikshospitalet in Oslo,Norway. in 1897.
Dr. Schiøtz devised this impression tonometer in 1905. It was applied against the sclera of the eye.
He later developed this into a corneal plunger. The higher the pressure inside of the eye, the lower amount of indentation that would result.
For the next fifty years, the Schiøtz tonometer was accepted as the reliable means of measuring intra-ocular pressure.
It required a calibration scale, which was designed by a Dr. Friedenwald. One had to take into account that placing a tonometer on the eye would raise the eye’s pressure.

Schiøtz manufactured the instruments personally. From the 1920’s he offered a calibration service in Norway for some years before licensing various companies, including Weiss & Co and Theodore Hamblin Ltd, to produce it. At the time of its introduction, the Schiøtz tonometer had the advantage that the pressure from the fingers holding the instrument was negligible. It was slightly modified in 1924 when an un-weighted version, the X-tonometer, was introduced. In 1955, the most recent version of the tonometer was introduced and used until it has been almost completely replaced in the West by applanation tonometry.

The model here was from about 1924 as seen from the paper insert that came with the instrument.