Optic Nerve Head and Retinal Nerve Fiber Layer Analysis in Ocular Hypertension and Early-Stage Glucoma Using Spectral-Domain Optical Coherence Tomography Copernicus

Objectives: Evaluation of structural alterations of the optic nerve head (ONH) and the retinal nerve fiber layer (RNFL) in patients with ocular hypertension (OHT) and early-stage glaucoma and assessment of the discriminatory diagnostic performance of spectral-domain optical coherence tomography (SD-OCT) Copernicus (Optopol Technology S.A.). Materials and Methods: This study included 59 eyes of a total of 59 patients, 29 of whom were diagnosed with OHT (Group 1) and 30 with early-stage glaucoma (Group 2). The differentiation of early-stage glaucoma and OHT was carried out on the basis of standard achromatic visual field test results. Analysis of the ONH and RNFL thickness of all cases was made using SD-OCT. Group 1 and Group 2 were compared with respect to the ONH parameters and RNFL thickness. The diagnostic sensitivity of the OCT parameters was evaluated by the area under the receiver operating characteristics curves (AUC). Results: The average, superior, inferior, and nasal RNFL thicknesses in early-stage glaucoma cases were approximately 10% (12-14 µm) less compared to the OHT eyes, with differences being highly significant (p≤0.001). However, there was no statistically significant difference in the temporal RNFL thicknesses. The most sensitive parameter in the early diagnosis of glaucoma was average RNFL thickness corresponding to AUC: 0.852, followed by AUC: 0.816 and AUC: 0.773 values in superior and inferior RNFL thickness, respectively. In localized RNFL defects, the highest sensitivity corresponded to superior and superonasal quadrants (ACU: 0.805 and ACU: 0.781, respectively). There were not any statistically significant differences between the ONH morphological parameters of the two groups. Conclusion: RNFL analysis obtained using SD-OCT Copernicus is able to discriminate early-stage glaucoma eyes from those with OHT. However, ONH morphological parameters do not have the same diagnostic sensitivity. Turk J Ophthalmol 2014; 44: 35-41)