GDx-VCC Performance to Discriminate Normal, Pre-perimetric Glaucomatous Eyes

ABSTRACT

PURPOSE: This study was designed to assess the diagnostic value of scanning laser polarimetry with variable corneal compensation (GDx-VCC) in the diagnosis of preperimetric glaucoma. METHODS: The study included 132 eyes of 132 patients with normal intraocular pressure, including 38 normal eyes, 60 eyes with pre-perimetric glaucoma, and 34 eyes with early glaucoma. The parameters of GDx-VCC were analyzed and compared in these groups using ANOVA. The parameter with the most powerful diagnostic value was defermirred by an ROC curve, and it's sensitivity and specificity were calculated. RESULTS: Among GDx-VCC parameters, NFI was the most valuable parameter that could detect pre-perimetric glaucoma in normal eyes. A cut-off value of 12 was the optimal NFI value, which offered the highest sensitivity and specificity in discriminating between normal and pre-perimetric glaucomatous eyes. However, there were no statistically significant differences in GDx-VCC parameters between pre-perimetric and early glaucomatous eyes. A statistically significant correlation was found between NFI and visual field indices in early glaucomatous eyes. CONCLUSIONS: GDx-VCC can be useful as a screening test for early detection of pre-perimetric and early glaucoma with normal intraocular pressure.