Systematic review of the agreement of tonometers with Goldmann applanation tonometry

Objective: To assess the agreement of tonometers available for clinical practice with the Goldmann applanation tonometer (GAT), the most commonly accepted reference device.

Design: A systematic review and meta-analysis of directly comparative studies assessing the agreement of 1 or more tonometers with the reference tonometer (GAT).

Participants: A total of 11 582 participants (15 525 eyes) were included.

Methods: Summary 95% limits of agreement (LoA) were produced for each comparison.

Main outcome measures: Agreement, recordability, and reliability.

Results: A total of 102 studies, including 130 paired comparisons, were included, representing 8 tonometers: dynamic contour tonometer, noncontact tonometer (NCT), ocular response analyzer, Ocuton S, handheld applanation tonometer (HAT), rebound tonometer, transpalpebral tonometer, and Tono-Pen. The agreement (95% limits) seemed to vary across tonometers: 0.2 mmHg (-3.8 to 4.3 mmHg) for the NCT to 2.7 mmHg (-4.1 to 9.6 mmHg) for the Ocuton S. The estimated proportion within 2 mmHg of the GAT ranged from 33% (Ocuton S) to 66% and 59% (NCT and HAT, respectively). Substantial inter- and intraobserver variability were observed for all tonometers.

Conclusions: The NCT and HAT seem to achieve a measurement closest to the GAT. However, there was substantial variability in measurements both within and between studies.