The glaucoma detection capability of spectral-domain OCT and GDx-VCC deviation maps in early glaucoma patients with localized visual field defects

Abstract

To evaluate and compare the glaucoma detection capabilities afforded by retinal nerve fiber layer (RNFL) thickness and deviation maps obtained using Cirrus spectral domain optical coherence tomography (Cirrus OCT), and GDx employing variable corneal compensation (GDx-VCC) in glaucoma patients with early, localized visual field (VF) loss. This prospective controlled, comparative study was performed on 42 eyes with localized VF defects, and 42 age/refractive error-matched healthy eyes. All participants were imaged by both imaging devices at the same visit. The area of the RNFL defect in each deviation map, corresponding to a VF defect, was analyzed by direct counting of color-coded superpixels in each device. Receiver operating characteristic (ROC) curves were constructed and compared between Cirrus OCT and GDx-VCC. The areas under the ROCs (AUCs) of RNFL quadrant thicknesses in hemifields with visual field (VF) defects did not differ significantly (Cirrus OCT; 0.961, GDx-VCC; 0.919, P = 0.07). However, Cirrus OCT afforded a better diagnostic ability, by deviation map analysis, than did GDx-VCC (0.972 vs 0.887, P = 0.02). The RNFL thicknesses assessed by either Cirrus OCT or GDx-VCC were comparable in terms of early glaucoma diagnostic capability. However, when areas containing RNFL defects were analyzed via deviation mapping, Cirrus OCT was better than GDx-VCC.