Diagnostic accuracy of AS-OCT vs gonioscopy for detecting angle closure: a systematic review and meta-analysis.

PURPOSE: This study aims to review the literature that compares the accuracy of Anterior Segment-Optical Coherence Tomography (AS-OCT) against gonioscopy in detecting eyes with angle closure. It is currently unclear how AS-OCT fits into clinical practice for detecting angle closure. This is a systematic review and meta-analysis. METHODS: A literature search was performed on Medline, Embase, Scopus and the Cochrane Central Register of Controlled Trials to identify studies that investigated the diagnostic accuracy of AS-OCT in detecting eyes with angle closure as diagnosed by gonioscopy. Eligible studies included in the analysis met stringent inclusion criteria determining the sensitivity and specificity of AS-OCT. RESULTS: The initial search identified 727 studies, of which 23 were included in the final analysis. We found substantial variation in the parameters being studied and methodologies. The sensitivity of AS-OCT ranged from 46 to 100% (median 87%). Twenty-one studies identified parameters that showed sensitivity above 80%. The specificity ranged from 55.3 to 100% (median 84%). CONCLUSION: AS-OCT demonstrates good sensitivity for detecting angle closure. It may provide an avenue to address high rates of undiagnosed angle closure, such as found in developing Asian countries. However, AS-OCT is not yet able to replace gonioscopy. Clinicians should consider whether the diagnostic accuracy of AS-OCT is acceptable for their specific clinical use before adopting it. More studies are needed to determine the utility of AS-OCT, including longitudinal studies to determine the significance of eyes classified to have closed angles by AS-OCT but open on gonioscopy.

Comparison of central corneal thickness measurements by ultrasound pachymetry and 2 new devices, Tonoref III and RS-3000.

PURPOSE: There is currently little evidence assessing the repeatability and accuracy of central corneal thickness measurements using the devices Tonoref III and RS-3000. This study aims to compare these devices against measurements by ultrasound pachymetry. METHODS: Central corneal thicknesses were measured on 50 eyes. Measurements from two non-contact devices-Tonoref III (NIDEK CO., LTD, Gamagori, Japan) and RS-3000 (NIDEK CO., LTD, Gamagori, Japan)-were compared against ultrasound pachymetry, the gold standard. Ultrasound measurements were obtained using a 'Pachmate' device (DGH Technology, Inc, Exton, PA, USA). Repeatability was defined as the value that the difference between two consecutive measurements falls below 95% of the time. The within-subject standard deviation and repeatability values were calculated for Pachmate and Tonoref III by one-way ANOVA. Repeatability of RS-3000 was determined by nonparametric analysis. Agreement between Tonoref III and Pachmate was assessed by a Bland-Altman plot. Agreement between RS-3000 and Pachmate was assessed by nonparametric analysis. RESULTS: The Pachmate, Tonoref III and RS-3000 had repeatability values of 16, 7.4 and 5 µm, respectively. The mean difference between Tonoref III and Pachmate was - 15 µm (95% LoAs - 31 to + 0 µm). The median value for the difference between RS-3000 and Pachmate was - 4 µm (95% of values within - 24 and + 4 µm). CONCLUSION: The Tonoref III and RS-3000 showed good repeatability when compared to ultrasound pachymetry. However, neither instrument agreed interchangeably with CCT measurements by ultrasound pachymetry. Practitioners should determine whether the level of agreement is sufficient to meet their clinical needs.