Using High-Resolution SD-OCT to Detect Changes in Retinal Thickness in Neuromyelitis Optica Spectrum Disorders

Abstract

Objective: We used ultra-high resolution spectral domain optical coherence tomography (UHR-OCT) to analyze the subclinical changes in retinal neurons, axon injury, and retinal thickness in neuromyelitis optica spectrum disorders (NMOSD) patients. Methods: This case-control study included 21 cases of NMOSD patients and 20 matched healthy volunteers (control group). The NMOSD patients were divided into a subgroup without optic neuritis (NO-ON) (13 eyes) and a subgroup with optic neuritis (ON) group (13 eyes). The thickness of the total retina of each patient and control subject was evaluated by using UHR-OCT. Data of each layer were analyzed using one-way ANOVA. Results: Except at the central region, the total retinal thickness of the ON group in whole mapping images was significantly thinner than the control group and NO-ON group. There were significant differences in total thickness between the NO-ON group and the control group in some regions (nasal interior [NI], P=0.011; temporal interior[TI], P=0.003; superior exterior [SE], P=0.019; inferior exterior [IE], P=0.002). The thicknesses of the retinal nerve fiber layer (RNFL) and the combined ganglion cell layer and inner plexiform layer (GCL+IPL) in the ON group was significantly thinner in each quadrant compared with the control group (P < 0.001). The RNFL thickness of the NO-ON group was thinner in the nasal and temporal areas compared with the control group (NI, P=0.049; TI and temporal exterior [TE], P < 0.001). The GCL+IPL thickness in the NO-ON group was thinner than control group (SE, P < 0.001; IE, P=0.002). The thickness of inner nuclear layer (INL) in the ON group was thicker than in the control group (superior interior [SI], P=0.001; inferior interior [II], P=0.003; TE, P=0.043); however the thickness of the INL in the NO-ON group was thinner than in the control group (SE, P=0.015; IE, P=0.012). The thickness of Henle fiber layer and outer nuclear layer (HFL+ONL) in the NO-ON group was thinner than for the control group (SI, P=0.009; SE, P=0.018; II, P=0.001; IE, P=0.001 ), but there were no significant differences between the ON group and the control group. Conclusions: There were significant changes in the different retinal layers of NMOSD patients compared to healthy controls. The thicknesses of RNFL and GCIPL in the NO-ON subgroup were decreased, suggesting that NMOSD patients with no optic neuritis potentially have structural damage in the retinal nerve. Key words: neuromyelitis optica spectrum disorders; optical coherence tomography; neuro damage; aquaporin-4