Every ophthalmologist has at one time or another doubted the reliability of his tonometer. It is obvious that any measuring device must be based on a standard. Even the length of a yardstick is determined by the Bureau of Standards. Yet there exists the anomalous situation that each ophthalmologist must establish the norms for his own instrument, which may not correspond to any other instrument.
EARLY CHECKING STATIONS
The Schiøtz tonometer, since its introduction in 1905, has gained universal recognition and is accepted as the standard. Since Schiøtz did not patent his tonometer, numerous competitive imitations came on the market, mainly of German manufacture. With them arose the necessity for checking the accuracy of tonometers. Checking stations were organized in Germany by Arnold and Karpow in 19231 and by Comberg in 1928.2 In 1925 Schiøtz3 announced a checking station at Oslo, Norway, under his own supervision. In
POSNER A. STANDARDIZATION AND CHECKING OF SCHIØTZ TONOMETERS. Arch Ophthalmol. 1943;30(1):1–13. doi:10.1001/archopht.1943.00880190015001
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