Prevalence of Calibration Errorsin Goldmann Applanation Tonometers

Purpose: to determine the prevalence of calibration errors in goldmann applanationtonometers at farabi eye hospital.methods: this cross-sectional study was performed on all tonometers in use at farabieye hospital. all haag-streit goldmann applanation tonometers were checkedaccording to the manufacturer’s method by two independent observers and by a third observer in case of mismatched results. calibration errors were classified into 6categories of ±0.5, ±1, ±1.5, ±2, ±2.5 and more than ±2.5 mmhg.results: overall, 43 goldmann tonometers were evaluated. there were 3 (7%), 10(24.3%), 16 (38.3%), 24 (56.9%), 31 (72.1%) and 12 (27.9%) tonometers within calibration errors of ±0.5, ±1, ±1.5, ±2, ±2.5 and more than ±2.5 mmhg respectively.conclusion: goldmann tonometers were not within the manufacturer's recommended range (±0.5 mmhg) in 93%, and not within the acceptable range of ±2.5 mmhg in 28%of checked devices. further study is needed to demonstrate the correlation between calibration errors and clinical errors.