Lamina Cribrosa Morphology in Normal Tension Glaucoma According to the Location of Visual Field Defects

Abstract

Précis: The morphologic alterations in lamina cribrosa (LC) may be related to the location of visual field (VF) defects. Purpose: The aim of this study was to investigate morphologic differences in the LC in normal tension glaucoma (NTG) according to the location of VF defects. Design: This study was a retrospective, cross-sectional study. Methods: Ninety-six eyes of 96 patients with NTG were included in this study. The patients were divided into 2 groups according to the location of VF defects [parafoveal scotoma (PFS) and peripheral nasal step (PNS)]. All patients underwent an optical coherence tomography of the optic disc and macula using swept-source optical coherence tomography (DRI-OCT Triton; Topcon, Tokyo, Japan). The parameters of the optic disc, macula, LC, and connective tissues were compared between the groups. The relationships between the LC parameters and other structures were analyzed. Results: The temporal peripapillary retinal nerve fiber layer, average macular ganglion cell-inner plexiform layer, and average macular ganglion cell complex were significantly thinner in the PFS than in the PNS group (P<0.001, P<0.001, and P=0.012, respectively). The PFS group showed a more glaucomatous LC morphology with a smaller lamina cribrosa-global shape index (LC-GSI, P=0.047), more LC defects (P=0.034), and thinner LC (P=0.021) than the PNS group. LC-GSI was significantly correlated with LC thickness (P=0.011) but not with LC depth (P=0.149). Conclusions: In patients with NTG, those with initial PFS showed a more glaucomatous LC morphology than those with initial PNS. The morphologic differences in LC may be related to the location of the VF defects.