Retinal nerve fibre layer evaluation in ocular hypertensive eyes using optical coherence tomography and scanning laser polarimetry in the diagnosis of early glaucomatous defects.

Abstract

To evaluate and compare the accuracy of scanning laser polarimetry with variable corneal compensation (GDx-VCC) and optical coherence tomography (OCT) for detecting glaucomatous damage observed in retinal nerve fibre layer (RNFL) monochromatic photographs from ocular hypertensive (OHT) individuals with normal visual fields. A total of 181 eyes from 181 patients with intraocular pressure >22 mm Hg were enrolled in a cross-sectional, hospital clinic-based study. All patients underwent full ophthalmological examination, standard automated perimetry, red-free digital RNFL photographs, and RNFL imaging with Stratus OCT and GDx-VCC. Subjects were divided into two groups according to observations from RNFL photographs: 128 OHT subjects without and 53 OHT subjects with RNFL defects. Receiver operating characteristic (ROC) curves plotted for the RNFL parameters were compared between OCT and GDx-VCC. The OCT parameter with the highest diagnostic accuracy for detecting early RNFL defects was average thickness, and for the GDx-VCC was temporal-superior-nasal-inferior-temporal average, with areas under the ROC curve of 0.785 and 0.758, respectively (all AUCs p<0.001). OCT and GDx have similar diagnostic accuracy for identifying early defects detected by RNFL monochromatic photography in OHT patients.