A NEW METHOD FOR THE AUTOMATIC TESTING OF APPLANATION TONOMETERS

摘要

The exact measurement of the intraocular pressure is of great diagnostic importance in the field of ophthalmology. According to the international standard DIN EN ISO 8612, the tonometers being used are subject to strict type approval and, furthermore, must be checked on a regular basis. For calibration of one of the most widely used and most precise tonometers known as applanation tonometers usually a mechanical cross-beam balance is being employed at present. However, as the use of this type of test equipment requires a lot of time and yields test results of limited accuracy only, it does no longer meet the requirements of an objective, metrological quality control. When using other conventional weighing or also force measuring equipment, such as DMS sensors or electromagnetically force-compensated balances, it was not possible to obtain the required parameters either because of insufficient accuracy or the prescribed horizontal service position. With the aim to provide a solution to the above problem, this paper presents a new, optical interference test equipment which permits to carry out an automated test procedure of applanation tonometers of various types at very high speed, thus reducing the testing times of about 30 minutes at present to 5 minutes.