Detection of nerve fiber bundle defects with laser polarimetry in glaucoma: a clinical study with the Nerve Fiber Analyzer I

Purpose: To verify whether nerve fiber bundle defects (NFBD) can be detecte d by the polarization technique of the Nerve Fiber Analyzer \ (NFA \), we c ompared the localization of localized visual field (VF) defects with the lo calization of the expected corresponding NFBD. Methods: We examined 25 eyes of 25 glaucoma patients. All examined glaucoma tous eyes had localized VF defects stage II and III. The glaucoma stage was defined by examination of the central 30 degrees VF using computer perimet ry. NFBD were determined by masked examination of NFA I images by three exa miners. As controls 22 eyes of 22 normals were examined. Results: In 18 (72 %) of 25 glaucomatous eyes the three examiners agreed in their findings. In 15 of 25 glaucomatous eyes (60 %) all three examiners f ound a NFBD, which corresponded to a localized VF defect. In 18 of 22 healt hy eyes all three examiners found no NFBD. The first examiner had no false- positive results, the second three, and the third four. Conclusions: The three examiners often disagreed in their findings of NFBD, which indicates high subjective variability. Examiner-dependent specificit y and sensitivity show that detection of glaucomatous NFBD is often not pos sible by laser polarimetry (software version 06/93).