AIM:To evaluate the optic nerve and axon impairment of relapsing-remitting multiple sclerosis(RRMS)and neuromyelitis optica spectrum disorders(NMOSD)via detecting the peripapillary retinal nerve fiber layer(pRNFL)and the ganglion cell complex(GCC)thickness by optic coherence tomography(OCT).

METHODS: Retrospective case control study. Two hundred three cases were collected from August 2014 to January 2016 in Beijing Tian Tan Hospital. They were divided into four groups, including the normal group(n=60), the RRMS group(n=60), the NMOSD anti-aquaporin-4 autoantibody seropositive(NMOSD-AQP4-Ab seropositive)group(n=48), and the NMOSD-AQP4-Abseronegative group(n=35). All people were detected for the average and four quadrants(superior, inferior, nasal, temporal)of pRNFL thickness and the average and two quadrants(superior, inferior)of GCC thickness with OCT. One way analysis of variance or nonparametric tests was used to compare the differences of pRNFL and GCC thickness between groups.

RESULTS: Comparing with the normal group, the average and all quadrants of pRNFL and GCC thickness in the RRMS, the NMOSD-AQP4-Ab seropositive and the NMOSD-AQP4-Ab seronegative group were thinner(P<0.01). Among them, the pRNFL and GCC thickness in the NMOSD-AQP4-Ab seropositive group was the thinnest. Differences between groups in the pRNFL thickness: compared with the RRMS group, all quadrants of pRNFL and GCC thickness in the NMOSD-AQP4-Ab seropositive group were significantly thinner(P<0.01); compared with the NMOSD-AQP4-Ab seronegative group, the inferior, nasal and temporal pRNFL thickness in the NMOSD-AQP4-Ab seropositive group were significantly thinner(P<0.05), while the superior quadrant did not show significant differences(P>0.05); compared with the RRMS group, the superior pRNFL thickness in the NMOSD-AQP4-Ab seronegative group was significantly thinner(P<0.05), while the inferior, nasal and temporal quadrants did not show significant differences(P>0.05). Differences between groups in the GCC thickness: compared with both the RRMS and the NMOSD-AQP4-Ab seronegative group, all quadrants of GCC thickness in the NMOSD-AQP4-Ab seropositive group were significantly thinner(P<0.05); compared with the RRMS group, the superior GCC thickness in the NMOSD-AQP4-Ab seronegative group was significantly thinner(P<0.01), while the inferior quadrant did not show significant difference(P>0.05).

CONCLUSION: The optic nerve and axon impairment in NMOSD-AQP4-Ab seropositive group was the most severe and the impairment in RRMS group was the least severe. The impairment in NMOSD-AQP4-Ab seronegative group was between the former two, and could be more similar to that of RMMS.