SHOULD TONOMETRY BE REPEATED - STATISTICA L-ANALYSIS OF 64 MEASUREMENTS FOR 25 PATIENTS

Purpose This study aimed to determine usefulness of repeating tonometr y and averaging of the results in order to increase precision. Methods Variance analysis was performed, the intra class correlation coeffici ent was calculated to determine the confidence intervals (95 %) for av eraging with two or more results. Results For one measurement the conf idence interval was 7.07 mmHg, for 2 measurement, in order to increase 5.00 mmHg and for 3 measurement 4.08 mmHg. For more measurements, the re was little more improvement in precision. Conclusion We therefore r ecommend to perform the tonometry twice, averaging the 2 results, in o rder to increase the precision of the final result. If more precision is required a third measurement and averaging of the 3 results can be made. Although it was proven that the influence of carefully repeated aplanation tonometry is not significant on the resultats for 2 or 3 me asurements, averaging could be done during a single consultation.