Imaging nerve fiber bundle defects with laser polarimetry in glaucoma. A clinical study with the Nerve Fiber Analyzer I

Abstract

To verify whether nerve fiber bundle defects (NFBD) can be detected by the polarization technique of the Nerve Fiber Analyzer I (NFA I), we compared the localization of localized visual field (VF) defects with the localization of the expected corresponding NFBD. We examined 25 eyes of 25 glaucoma patients. All examined glaucomatous eyes had localized VF defects stage II and III. The glaucoma stage was defined by examination of the central 30 degrees VF using computer perimetry. NFBD were determined by masked examination of NFA I images by three examiners. As controls 22 eyes of 22 normals were examined. In 18 (72%) of 25 glaucomatous eyes the three examiners agreed in their findings. In 15 of 25 glaucomatous eyes (60%) all three examiners found a NFBD, which corresponded to a localized VF defect. In 18 of 22 healthy eyes all three examiners found no NFBD. The first examiner had no false-positive results, the second three, and the third four. The three examiners often disagreed in their findings of NFBD, which indicates high subjective variability. Examiner-dependent specificity and sensitivity show that detection of glaucomatous NFBD is often not possible by laser polarimetry (software version 06/93).