Enhanced Depth Imaging of Central Laminar Thickness in Optic Neuropathy: Comparison with Normal Eyes

The purpose of this study was to compare central laminar thickness (LT) among patients with glaucomatous optic neuropathy (GON), patients with non-GON, and normal subjects using enhanced-depth imaging optical coherence tomography (EDI-OCT). Enrolled were 57 patients (n = 64 eyes), including 30 women and 27 men. Three groups were identified: GON (n = 18 eyes), non-GON (n = 16 eyes), and control (n = 30 eyes). The GON group comprised eyes with primary open-angle glaucoma (POAG) (n = 9) and normal-tension glaucoma (NTG) (n = 9). The non-GON group comprised eyes with demyelinating optic neuritis (n = 9), anterior ischemic optic neuropathy (AION) (n = 2), compressive ON (n = 2), Leber hereditary ON (n = 2), and traumatic ON (n = 1). GON and non-GON groups were further divided into mild, moderate, and severe subgroups. Inclusion in the GON group was based on mean deviations (MDs) of visual fields; inclusion in the non-GON group was based on critical flicker frequency (CFF) responses. Intraclass correlation coefficients (ICCs) were used to verify reproducibility of measurements. LTs of GON and non-GON group eyes were thinner than those of control group eyes (p < 0.01); LTs of GON group eyes were thinner than those of non-GON group eyes (p = 0.01). LTs of severe GON subgroup eyes were thinner than those of moderate and mild GON subgroup eyes (p < 0.001; p = 0.024, respectively). LTs of severe non-GON subgroup eyes were thinner than those of mild non-GON subgroup eyes (p = 0.002). These results show that EDI-OCT is valuable for documenting structural abnormalities in optic neuropathy (ON).