Relationship Between Optic Nerve Head and Nerve Fiber Layer with Central Corneal Thickness in Primary Open Angle Glaucoma: A Three-Dimensional Optical Coherence Tomography Study

Özet

Introduction: To evaluate the relationship between optic nerve head (ONH) parameters and retinal nerve fiber layer (RNFL) thickness with central corneal thickness (CCT) in primary open angle glaucoma (POAG) patients using three-dimensional spectral domain optical coherence tomography (3D SD-OCT). Methods: In this cross-sectional study, 144 eyes of 144 patients (79 female, 65 male) with POAG were studied. Patients were classified into thick cornea group (Group 1) and thin cornea group (Group 2). Group 1 represented eyes with CCT ≥540 μm and Group 2 with CCT <540 μm. Topographic measurements of the ONH and peripapillary RNFL thickness was performed using 3D-OCT. The outcomes were correlated with the CCT of the subjects. Results: The mean age of the study population was 63.6±12.7 years (47–69 years). There was no statistically significant difference between the two groups in terms of age, sex, spherical equivalent refractive error, and mean intraocular pressure (p=0.52, p=0.45, p=0.34, p=0.65, respectively). The mean CCT of subjects was 556.6±34.37 μm (468–635 μm), and the mean disc area was 2.52 ± 0.47 mm2 (1.76–3.99 mm2). CCT showed a negative correlation with cup area (p=0.03), cup-disc area ratio (p<0.005), horizontal cup-disc ratio (p=0.04), and cup volume (p<0.005) and a positive correlation with rim area (p=0.025), rim volume (p=0.015), and inferior RNFL (p<0.005). No significant difference in optic disc area, vertical cup-disc ratio, average RNFL, and superior RNFL existed between the two groups (p=0.81, p=0.516, p=0.13, p=0.14, respectively). Discussion and Conclusion: POAG patients with thin corneas may be at greater risk of glaucomatous damage as measured by a cup-disc ratio, neuro-retinal rim, and RNFL.