Enhanced depth imaging detects lamina cribrosa thickness differences in normal tension glaucoma and primary open-angle glaucoma.

Abstract

To confirm the advantages of the enhanced depth imaging (EDI) mode over the standard mode of the Heidelberg Spectralis spectral domain optical coherence tomography (SD-OCT) for imaging of the lamina cribrosa, and to compare laminar thicknesses of various glaucoma types with or without disc hemorrhage in a similar state of visual field loss. Cross-sectional, case-control design. We included 137 glaucoma patients and 49 healthy controls. Optic nerve head B-scans were obtained by both the standard and EDI modes of the Spectralis OCT. Laminar thickness was measured at the center of mid-superior, central, and mid-inferior horizontal B-scans. Laminar thickness in patients with normal tension glaucoma (NTG) was compared with that in patients with primary open-angle glaucoma (POAG). To verify the reproducibility of EDI imaging, intraclass correlation coefficients and test-retest variability were calculated from selected B-scans. Laminar thickness and mean deviation values on standard automatic perimetry. The EDI OCT imaging showed significantly better intraobserver, interobserver, intravisit, and intervisit reproducibility than those by standard imaging. Laminar thickness in mid-superior, central, and mid-inferior regions was thinner in the POAG and NTG groups than in the normal control group (P<0.001). The mid-superior, central, and mid-inferior regions of the lamina were also significantly thinner in patients with NTG and disc hemorrhage than in those with NTG but no disc hemorrhage. The EDI mode of the Heidelberg Spectralis SD-OCT detected differences in the lamina cribrosa by glaucoma type. The lamina cribrosa was thinner in NTG eyes and in NTG eyes with disc hemorrhage. The authors have no proprietary or commercial interest in any of the materials discussed in this article.