Measurement of Scleral Thickness using Swept-Source Optical Coherence Tomography in Open-Angle Glaucoma Patients with Myopia – Accepted Manuscript

Abstract: Purpose: To use swept-source optical coherence tomography (OCT) to image the posterior sclera at the posterior pole and around the optic nerve head (ONH), and measure the subfoveal scleral thickness and laminar thickness to evaluate the relationship between the measured thicknesses and ocular parameters.Design: Prospective, cross-sectional design.Methods: One hundred and twelve glaucoma patients and 46 controls with axial length more than 26 mm were enrolled. Swept-source OCT images were obtained to capture the subfoveal and ONH region. Subfoveal scleral thickness and laminar thickness were measured from obtained B-scan images. To verify the reproducibility of the measurement, intraclass correlation coefficients were calculated from selected B-scans. Scleral and laminar thickness in patients with normal tension glaucoma (NTG) was compared with that in patients with primary open angle glaucoma (POAG). Pearson’s correlation was calculated to assess the relationships of scleral and laminar thicknesses with ocular parameters.Results: Posterior scleral thickness could be measured in 68.4% and laminar thickness could be measured in 88.6% using swept-source OCT. Interobserver and intraobserver measurement reproducibility was moderate to excellent. The subfoveal scleral thickness was 670.84 ± 160.60 μm in the POAG group and 496.55 ± 115.20 μm in the NTG group, which was significantly different between groups. Subfoveal scleral thickness (r = -0.677, P < 0.001) was negatively correlated with axial length only in NTG patients, not POAG patients.Conclusions: Swept-source OCT detected differences in the thickness of the posterior sclera between NTG and POAG eyes. Subfoveal scleral thickness was negatively correlated with axial length only in NTG eyes.