[Sensitivity and specificity of the Heidelberg retinal tomograph for imaging nerve fiber bundle defects in glaucoma...

In order to verify whether nerve fiber bundle defects can be detected by the confocal technique of the Heidelberg Retina Tomograph (HRT), we compared the localization of localized visual field defects with the localization of the expected corresponding nerve fiber bundle defect. We examined 105 patients: 49 with primary open-angle glaucoma (POAG), 26 with low-tension glaucoma (LTG) and 10 with ocular hypertension (OH), and as a control-group 20 healthy eyes. The glaucoma stage had been defined by examination of the central visual field with the Octopus Perimeter 201 program 31 or 32 and/or the Humphrey Perimeter GG program. In healthy eyes, eyes with OH and POAG stage I (n = 19), no nerve fiber bundle defect could be found. In stage II (n = 15) and stage III (n = 14) we found nerve fiber bundle defects in all patients with POAG and LTG (except for one patient with POAG stage III). In stage IV (n = 27) no localized nerve fiber bundle defects were detected in eyes with POAG, but in 4 of 7 patients with LTG, defects could be seen. In glaucoma stages II and III, nerve fiber bundle defects can be detected with the HRT. The control group shows, that the appearance of a nerve fiber bundle defect is no artifact caused by the HRT. However, examination of eyes with OH and POAG stage I also shows that this method is not sensitive enough to be useful for early diagnosis of glaucoma. Nevertheless, it may be possible to develop the confocal HRT method further as a nerve-fiber diagnostic method for glaucoma.