Bechrakis E, Weigelin E
Klin Monbl Augenheilkd. 1978 Dec;173(6):825-9.
The hand held applanationstonometer Draeger gives reliable measurements of intraocular pressure, they correspond of those from Goldmann applanationstonometer. The eventual value deviations of i. o. pressure at the beginning of the tests are not caused by the instrument but mainly by the effect of repeated applanation tonometry.