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Diagnostic accuracy of optical coherence tomography for diagnosing glaucoma: secondary analyses of the GATE study


Background/Aims To assess the diagnostic performance of retinal nerve fibre layer (RNFL) data of optical coherence tomography (OCT) for detecting glaucoma.

Methods Secondary analyses of a prospective, multicentre diagnostic study (Glaucoma Automated Tests Evaluation (GATE)) referred to hospital eye services in the UK were conducted. We included data from 899 of 966 participants referred to hospital eye services with suspected glaucoma or ocular hypertension. We used both eyes’ data and logistic regression-based receiver operator characteristics analysis to build a set of models to measure the sensitivity and specificity of the average and inferior quadrant RNFL thickness data of OCT. The reference standard was expert clinician examination including automated perimetry. The main outcome measures were sensitivity at 0.95 specificity and specificity at 0.95 sensitivity and the corresponding RNFL thickness thresholds. We explored the possibility of accuracy improvement by adding measures of within-eye and between-eye variation, scan quality, intraocular pressure (IOP) and age.

Results Glaucoma was diagnosed in at least one eye in 17% of participants. Areas under the curve were between 0.83 and 0.88. When specificity was fixed at 0.95, the sensitivity was between 0.38 and 0.55, and the highest values were reached with models including the inferior quadrant rather than the average RNFL thickness. Fixing sensitivity at 0.95, the specificity was between 0.36 and 0.58. The addition of age, refractive error, IOP or within-subject variation did not improve the accuracy.

Conclusion RNFL thickness data of OCT can be used as a diagnostic test, but accuracy estimates remain moderate even in exploratory multivariable modelling of aiming to improve accuracy.

  • glaucoma
  • imaging
  • diagnostic tests/investigation

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  • Contributors GV proposed the idea of the secondary analysis of the study, and GV, MM, JC, JB, CB, CRR and AA-B made substantial contributions to the conception and design of the work. RRAB, DFG-H and AA-B contributed to data acquisition. Substantial contributions to data analysis were made by GV, CB and JC. All authors provided substantial contributions to the interpretation of data, drafting the work or revising it critically for important intellectual content, and approved the final version. All authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Competing interests None declared.

  • Ethics approval Institutional Review Board (IRB)/EthicsCommittee approval was obtained for the GATE study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Correction notice This article has been corrected since it was published Online First. In the ’Results' paragraph of the Abstract, the sentence "Fixing specificity at 0.95, the sensitivity was between 0.36 and 0.58.” has been corrected to: “Fixing sensitivity at 0.95, the specificity was between 0.36 and 0.58.”.

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