Agreement and Reliability of Transpalpebral Tonometers with Goldmann Applanation Tonometer: A Systematic Review and Meta-analysis.

Topic: The systematic review and meta-analysis consolidates the extant body of evidence comparing reliability and agreement between transpalpebral tonometers (TTs) and Goldmann applanation tonometer (GAT).

Clinical relevance: With a global prevalence of 3.54 percent, glaucoma stands as the second leading cause of preventable blindness. Projections indicate a rise to 111 million cases by 2040. Existing literature presents inconsistent findings while comparing TT and GAT. The derivation of summary estimates assessing their agreement holds significance, given TT's multifaceted applicability in clinical, community, and home settings.

Methods: Systematic review was conducted using PubMed, Cochrane Library, and Google Scholar from January 2000 to December 2022. Two reviewers independently evaluated, enumerated, and extracted studies and data based on eligibility criteria. The Quality Assessment for Diagnostic Accuracy Studies checklist was used to assess study quality. The summary measures were pooled using the random-effects model as mean difference (MD), and 95% limits of agreement (LoA). We assessed heterogeneity using the I² statistic. The study protocol was registered with the International Prospective Register of Systematic Reviews (CRD42022321693).

Results: A total of 26 methods comparison studies (3577 eyes) were included in the meta-analysis. The overall random-effects MD (TT - GAT) and standard deviation (SD) for intraocular pressure (IOP) were -0.70 ± 4.32 mmHg (95% LoA: -8.74 to 7.33 mmHg). In the subgroup analysis based on index test devices used, Easyton showed the lowest MD, SD, (-0.29 ± 2.35 mmHg), and 95% LoA (-4.90 to 4.32 mmHg). In the univariate meta-regression model, we found that, on average, studies examining normal eyes reported a statistically significant lower MD of 2.67 mmHg (95% confidence interval: 0.27-5.07 mmHg; P = 0.03) between TT and GAT, compared to studies that assessed eyes with mixed ocular condition.

Conclusion: In the current meta-analysis, we found a small MD in the measured IOP between the 2 tonometers. However, given the high heterogeneity and a wider LoA, it is not advisable to use TT interchangeably with GAT.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.