Diagnostic ability of Heidelberg Retina Tomograph 3 classifications: glaucoma probability score versus Moorfields regression analysis

Abstract

Purpose: To evaluate the usefulness of the glaucoma probability score (GPS), which does not require manual outlining of the disc boundaries, and the Moorfields regression classification (MRA), which requires manual outlining of the disc boundaries, for discriminating between healthy and glaucomatous eyes, using the Heidelberg Retina Tomograph.

Design: Cross-sectional study.

Participants: We prospectively selected 71 consecutive healthy subjects and 115 consecutive patients with open-angle glaucoma.

Methods: Participants were divided into 2 groups depending on the results of standard automated perimetry and intraocular pressure. All participants underwent imaging of the optic nerve head with the Heidelberg Retina Tomograph 3. All tests were performed within 1 month of each subject's date of enrollment into the study by examiners masked to the other findings.

Main outcome measures: The sensitivity and specificity of all parameters of the MRA and GPS classifications were calculated. The diagnostic accuracy at different severities of glaucoma and optic disc sizes was also evaluated. Receiver operating characteristic curves were plotted for the GPS values.

Results: The MRA global classification had a sensitivity of 73.9% and a specificity of 91.5%. The GPS global classification had a sensitivity of 58.2% and a specificity of 94.4%. The GPS had slightly higher sensitivity and somewhat lower specificity than the MRA when there was mild damage indicated by visual field tests. The MRA had the best discrimination capability for moderate and severe glaucoma. Both the GPS and MRA had lower sensitivity and higher specificity for small optic discs (<1.7 mm2) compared with medium and large discs.

Conclusions: In general, the diagnostic performance of the GPS was similar to that of the MRA. The diagnostic accuracy of both classifications depends on the optic disc size and the glaucoma severity.