Abstract
Abstract: :
Purpose:To compare retinal nerve fiber layer(RNFL) measurements obtained with red–free photography using HRA with scanning laser polarimetry(SLP) with variable corneal compensation (GDx VCC) with optical coherence tomography (Stratus OCT3) to discriminate between healthy eyes and preperimetric glaucomatous eyes and perimetric glaucomatous eyes. Methods: This observational, cross–sectional study included 1 eye of each of 39 patients with perimetric glaucoma (POAG:NTG=24:15), 42 patients preperimetric glaucoma, and 35 healthy subject. All individuals underwent imaging with RNFL red–free photography using HRA, GDx VCC, Stratus OCT3 as well as visual field testing simultaneously. Three independent observers graded RNFL photographs(from 1 point to 25 points) according to visibilities of nerve fiber bundle using a standardized photographic reference set. Receiver operating characteristic(ROC) curves and sensitivities at fixed specificities(80% and 95%) were calculated for parameters reported as continuous variables to assess the abilities of the different method to differentiate glaucoma patients from healthy subjects. Results:The best parameters were NFI( GDx VCC), Avg. Thick( Stratus OCT3), and Global RNFL photographic score to discriminate between normal healthy patients and preperimetric glaucoma patients(AUC=0.70, 0.74, and 0.95, respectively), as well as between normal patients and perimetric glaucoma patients ( AUC=0.90, 0.92, and 0.98, respectively). Between preperimetric glaucoma and perimetric glaucoma patients, TSNIT Avg.(AUC=0.77, GDx VCC), Iavg(AUC=0.77,Stratus OCT3), Inferior hemiretina photographic score(AUC=0.81) were the best parameters. When the specificity was set at 80%, the sensitivity of the Avg. Thick to diagnose glaucoma was 92% compared with 84% for the NFI. At high–specificity settings(90%), NFI and Avg. Thick had relatively low and similar sensitivities(40% and 36%, respectively) in our study. Conclusions: Compared with the best parameters of GDx VCC and OCT3, semiquantitative RNFL photographic scores using HRA which provide a higher resolution image than conventional red–free photography had a higher diagnostic accuracy to discriminate glaucoma patients from healthy subjects, which means still gold–standard to evaluate RNFL defect. Of the two, Stratus OCT3 had the better AUCs and sensitivities at moderate specificity(80%) than GDx VCC in our study. But each instrument may provide additional information to assist the clinician in diagnosing glaucoma.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical