PURPOSES: To verify the frequency of non-calibrated Goldmann's applanation tonometers and the influence of the following variables: model, age, number of daily examined patients and how often the tonometers are gauged. To evaluate the degree of knowledge by ophthalmologists about checking the calibration of this device. METHODS: The study was developed in Recife, Brazil. Seventy-nine Goldmann's tonometers in use were identified. The functioning of the tonometers was checked at the 0, 20 and 60 mmHg positions. Measurements with an error greater than ± 2 mmHg were considered significant. The following data were also recorded: model, age, number of daily examined patients and the frequency of calibration checking. One third (92) of the city's ophthalmologists were interviewed and asked whether they knew how to check the tonometer and if they did the checking themselves. RESULTS: Twenty tonometers (25.3%) were not calibrated. Thirty eight tonometers (48.1%) were fixed to the slit lamp and 41 (51.9%) were removable. Twenty-eight tonometers (35.4%) were less than 5 years old. Forty-eight devices (60.8%) were used daily in 20 patients or less. The frequency of calibration checking was annual or more frequently in 36 (45.6%) devices. Non-calibrated tonometers were more common among the removable ones and those older than 5 years (p=0.008 e p=0.050, respectively). Only 37 (40.2%) of the ophthalmologists knew how to check the tonometers. CONCLUSIONS: A quarter of the tonometers was not calibrated. The removable ones and those with more than 5 years of use were more prone to be non-calibrated. The majority of the ophthalmologists did not know how to check the tonometer.
Tonometry; Equipament and supplies; Measurement equipament
