Correlation of retinal nerve fiber layer thickness and perimetric changes in primary open-angle glaucoma

Purpose This study aims at evaluating the relation between retinal nerve fiber layer (RNFL) thickness evaluated by spectral-domain optical coherence tomography (OCT) in primary open-angle glaucoma and visual field sensitivity.Patients and methods A total of 20 normal and 60 glaucomatous eyes were included in this study. Glaucomatous eyes were graded into early, moderate and severe stages according to Hodapp, Parrish, and Anderson classification. Complete ophthalmic examination, white-on-white perimetry and spectral-domain OCT were done for all patients. RNFL thickness of quadrants and average thickness were recorded. Area under receiver operating characteristic curves were used to assess the performance of OCT parameters.Results Average RNFL thickness was the best parameter to discriminate normal from early glaucoma, early from moderate and moderate from severe. Average RNFL loss was 14.9% in early glaucoma, 25.1% in moderate glaucoma and 37.2% in severe glaucoma. A significant correlation was detected between mean deviation and average RNFL thickness.Conclusion The present study found that average RNFL thickness has a good diagnostic value for diagnosis of glaucoma and for differentiating between glaucoma stages according to its severity.