| Abstract: | Purpose. To evaluate the thickness of the retinal nerve fiber layer (RNFL) in healthy eyes and in eyes of patients with primary open angle glaucoma using the Heidelberg retina tomograph (HRT), the nerve fibre analyser (NFA) and the optical coherence tomograph (OCT). Methods. In this prospective cohort study, 40 normal eyes and 86 eyes of age-matched glaucoma patients were compared by confocal scanning laser tomography using the HRT, scanning laser polarimetry (NFA) and optical coherence tomography (OCT). The RNFL thickness was measured in the superior, inferior, nasal and temporal regions as well as the total circumference. Results. All three methods revealed a statistically significant difference between normal and glaucomatous eyes with respect to the mean RNFL thickness in the inferior and superior regions (p<0.001). The mean RNFL thickness in the superior region was 329 μm (HRT), 87 μm (NFA) and 94 μm (OCT) in healthy volunteers compared to 275 μm (HRT), 72 μm (NFA) and 82 μm (OCT) in the patient group. In the inferior region, it was 323 μm (HRT), 87 μm (NFA) and 93 μm (OCT) in healthy subjects versus 240 μm (HRT), 74 μm (NFA) and 83 μm (OCT) in glaucoma patients. Cut-off points to differentiate between normal and glaucomatous eyes could not be defined. There was no difference in the RNFL thickness of right and left eyes. Conclusions. In RNFL thickness measurements using HRT, NFA and OCT, glaucoma patients showed a significantly thinner RNFL in the superior and inferior areas compared to healthy volunteers. These results confirm the known histological and fundus photographic findings of RNFL thinning near the optic disc in glaucoma patients. Although RNFL thickness cannot be used to diagnose glaucoma in individual patients due to the high interindividual differences, the quantitative assessment of RNFL thickness may complement the diagnostic armamentarium as a sensitive parameter for diagnosing and monitoring glaucomas. |
