Use of Progressive Glaucomatous Optic Disk Change as the Reference Standard for Evaluation of Diagnostic Tests in Glaucoma
Accepted 3 January 2005.
Purpose
Progressive change in optic disk appearance has been suggested as the best available reference standard for glaucoma diagnosis. We evaluated the accuracy of scanning laser polarimetry (SLP) with variable corneal compensation to discriminate patients with documented progressive optic disk change from healthy subjects.
Design
Observational case-control study.
Methods
Glaucoma patients with documented evidence of progressive optic disk change as assessed by stereoscopic photographs were selected. Healthy control subjects had normal visual fields and normal clinical examination. All subjects underwent imaging with the GDx VCC scanning laser polarimeter. Receiver-operating characteristic (ROC) curves, sensitivities at fixed specificities, and likelihood ratios were calculated.
Results
Sixty-five eyes were healthy control patients. Seventy-one eyes had progressive optic disk change, of which 41 (58%) had abnormal visual field tests closest to the imaging date (perimetric glaucomatous optic neuropathy [GON]), and 30 (42%) eyes had normal visual fields (preperimetric GON). The GDx VCC parameter nerve fiber indicator performed best for discrimination between perimetric GON and normal eyes (AUC = 0.94; sensitivity = 93% for specificity ≥80%) as well as for the discrimination between preperimetric GON and normal eyes (AUC = 0.89; sensitivity = 83% for specificity ≥80%).
Conclusion
SLP differentiated patients with documented progressive optic disk change from normal subjects and detected abnormalities in patients with confirmed diagnosis of preperimetric GON, suggesting that it may be useful for early glaucoma diagnosis. We suggest that progressive optic disk change should be used in the evaluation of diagnostic accuracy of imaging instruments for glaucoma.
Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, California.
Inquiries to Felipe A. Medeiros, MD, Hamilton Glaucoma Center, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0946
Supported in part by the Foundation for Eye Research (F.A.M.) and National Eye Institute grants EY11008 (L.M.Z.) and EY08208 (P.A.S.).
ABSTRACT