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

OBJECTIVE: 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.
DESIGN: Cross-sectional, case-control design. PARTICIPANTS: We included 137 glaucoma patients and 49 healthy controls.
METHODS: 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. MAIN OUTCOME MEASURES: Laminar thickness and mean deviation values on standard automatic perimetry.
RESULTS: 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.
CONCLUSIONS: 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. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.