[Diagnostic ability of GDx VCC for glaucoma diagnosis].

PURPOSE To assess the diagnostic ability of scanning laser polarimetry (GDx VCC) to differentiate between normal and glaucomatous eyes. METHODS 417 eyes of 417 consecutive subjects were prospectively selected. They were classified into 60 healthy controls, 218 ocular hypertensive eyes, 68 glaucoma suspects, and 71 glaucomatous eyes, depending on intraocular pressure, optic nerve head morphology and standard automated perimetry results. All underwent a scanning laser polarimetry with the GDx VCC. Retinal nerve fiber layer (RNFL) parameters of the GDx-VCC were compared among the four groups. Receiver operating characteristic (ROC) curves were plotted between normal and glaucomatous eyes. The best parameters were defined according to the area under the ROC curve and the best sensitivity/specificity balance. RESULTS Most parameters of GDx-VCC exhibited differences between the glaucoma group and the rest of the groups. Some parameters were also different between healthy patients and glaucoma suspects. The best parameter was the nerve fiber indicator (NFI; area under the ROC curve: 0.876). NFI, superior normalized area, and inferior normalized area yielded the highest sensitivities at 85% and 90% fixed specificity. CONCLUSIONS Most RNFL parameters measured with the GDx-VCC provided good diagnostic ability for open-angle glaucoma. The best GDx-VCC parameter in differentiating between normal and glaucomatous eyes was the NFI.