The diagnostic properties of a nerve-fiber analyzer in glaucoma

Patricia M. Khu, MD, MS; Edgardo U. Dorotheo, MD; Lawrence Tinio, MD; Cynthia P. Cordero, MS; Manuel B. Agulto, MD

Philippine Journal of Ophthalmology (Jun 2004)

The diagnostic properties of a nerve-fiber analyzer in glaucoma

Patricia M. Khu, MD, MS,
Edgardo U. Dorotheo, MD,
Lawrence Tinio, MD,
Cynthia P. Cordero, MS,
Manuel B. Agulto, MD

Affiliations

Patricia M. Khu, MD, MS: Department of Ophthalmology and Visual Sciences University of the Philippines Philippine General Hospital Manila, Philippines; Institute of Ophthalmology University of the Philippines Manila Manila, Philippines; Eye Referral Center Manila, Philippines
Edgardo U. Dorotheo, MD: Department of Ophthalmology and Visual Sciences University of the Philippines Philippine General Hospital Manila, Philippines
Lawrence Tinio, MD: Eye Referral Center Manila, Philippines
Cynthia P. Cordero, MS: Department of Clinical Epidemiology University of the Philippines College of Medicine Manila, Philippines
Manuel B. Agulto, MD: Department of Ophthalmology and Visual Sciences University of the Philippines Philippine General Hospital Manila, Philippines; Institute of Ophthalmology University of the Philippines Manila Manila, Philippines; Eye Referral Center Manila, Philippines

Journal volume & issue: Vol. 29, no. 2
pp. 66 – 72

Abstract

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Objective: To determine the diagnostic properties of the GDx 400 (Laser Diagnostic Technologies, San Diego, CA, USA) nerve-fiber analyzer in normal and in glaucoma patients compared with a battery of glaucoma tests used by glaucoma experts as gold standard. Methods: Patients with and without glaucoma underwent a complete eye evaluation, automated perimetry, scanning laser polarimetry with the GDx 400, and opticdisc photography. Two glaucoma experts graded each study eye. Two-by-two tables were constructed for 5 GDx parameters (average thickness, superior average, inferior average, ellipse average, and ellipse modulation) and the GDx number. Receiver operating characteristic (ROC) curves were generated. Results: The study included 355 patients (171 normal, 184 glaucoma). The mean values of the 5 GDx parameters were lower for the glaucoma than for the normal group. The sensitivity and specificity of the GDx 400 were 45.4% and 91.9% if the cutoff level of the GDx number was 71. Ellipse modulation (EM) measures have the best ROC curve with area under the curve of 0.725. Conclusion: The GDx 400 nerve-fiber analyzer is primarily used as a screening tool to detect the presence or absence of glaucoma. Its accuracy can be improved with use of continuous corneal compensator.

Published in Philippine Journal of Ophthalmology

ISSN: 0031-7659 (Print)
Publisher: Philippine Academy of Ophthalmology
Country of publisher: Philippines
LCC subjects: Medicine: Ophthalmology
Website: https://paojournal.com

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