Association Of Neuromyelitis Optica Spectrum Disorders And Multiple Sclerosis With Swept-source Optical Coherence Tomography And Swept-source Optical Coherence Tomography Angiography Findings

Objective:To investigate and quantitatively analyze the structure and microcirculation of retina and choroid in Neuromyelitis Optica Spectrum Disorders(NMOSD)and Multiple Sclerosis(MS)patients without Optic Neuritis(ON)and other visual impairment with Swept-Source optical coherence tomography(SS-OCT)and angiography(SS-OCTA),also comparing with healthy controls,to determine if NMOSD and MS patients without ON and other visual impairment have the structure and microcirculation changes in retina and choroid.Meanwhile,to investigate the possible relationship between abnormal changes in the structure and microcirculation and to clarify if those abnormities are potentially related to the severity of NMOSD and MS.Materials and Methods:A total of 28 NMOSD participants(46 eyes),34 MS participants(64 eyes)and48 healthy controls(96 eyes)were included in this cross-sectional study.All the NMOSD and MS participants were evaluated in the Neurology department.All the NMOSD,MS and healthy control participants were obtained the baseline information,underwent standard ophthalmic examination,SS-OCT and SS-OCTA examination.SS-OCT and SS-OCTA were performed centered on both the macula and the optic disc,within the 6mm×6mm area.The 3-mm ring were used for quantitation the thickness of peripapillary retinal nerve fiber layer(p RNFL)including five parts.While the Early treatment diabetic retinopathy study(ETDRS)rings were used for quantitation the thickness of GCIPL,inner nuclear layer(INL),outer retina and choroid in five parts.The ETDRS rings were also used for measuring the vessel density(VD),including superficial vascular complex(SVC),deep vascular complex(DVC),superficial vascular plexus(SVP),intermediate capillary plexus(ICP),deep capillary plexus(DCP)and choriocapillaris(CC)centered on the macula and the VD of radial peripapillary capillaries(RPCP),SVC and DVC centered on the optic disc,which also included five parts.The five parts mentioned above were average,the superior part(S),the temporal part(T),the inferior part(I)and the nasal part(N).Then the difference in both thickness and VD were compared among the three groups and between each pair of the them.The possible association between the SS-OCT structure parameters and SS-OCTA angio parameters were detected,including the thickness of p RNFL and the VD of RPCP in the optic disc and between the thickness of GCIPL and the VD of SVC centered on the macula.Finally,the potential associations between the abnormal SS-OCT and SS-OCTA parameters and the Expanded Disability Status Scale(EDSS)score were detected in the NMOSD and the MS group.The SPSS software(for MAC version 23.0,Chicago,IL,USA)was used for statistical analysis,Generalized Estimating Equation(GEE)were used for adjusting the correlation between two eyes and p value less than 0.05 was considered statistically significant throughout the study.Results:Compared with healthy controls,the NMOSD and MS participants had significantly thinner p RNFL(p=0.002,p=0.001)and GCIPL(p=0.006,p<0.001),in the MS groups,the thickness of nasal INL significantly decreased(p=0.022).In both the NMOSD and MS groups,the VD decreased significantly in superficial vascular microcirculation and choroid capillary microcirculation centered on the macula,also in superficial vascular microcirculation in the optic disc,while the VD increased in deep capillary microcirculation both centered in the macula and optic disc.There was no difference in these parameters between the NMOSD and MS groups.Meanwhile,in the NMOSD and MS groups,the positive correlations were found between the average thickness of p RNFL and the average VD of RPCP centered on the optic disc(r=0.828,p<0.001;r=0.747,p<0.001),also between the average thickness of p RNFL and the VD of RPCP in other parts.While between the average thickness of GCIPL and the average VD of macular SVC,there was also significantly positive association(r=0.782,p<0.001;r=0.644,p<0.001),also between the average thickness of GCIPL and the VD of SVC in other parts.Meanwhile,in the NMOSD group,the thickness of nasal part of p RNFL were found negatively related to the EDSS score(r=-0.371,p=0.022),while in the MS group,the result showed a negative correlation between the thickness of superior part of GCIPLand EDSS score(r=-0.355,p=0.007),also between the superior part of SVP in macula and EDSS score(r=-0.282,p=0.032).Conclusion:This study indicated that in NMOSD and MS patients without ON and other visual impairment,there have already some changes in both structure and microcirculation in retina and choroid.The abnormalities in the eye fundus of NMOSD and MS patients could be detected by SS-OCT and SS-OCTA in the early stage.SS-OCT and SSOCTA could help in the understanding of the potentially pathophysiology changes in the disease process,providing a relatively reliable reference for the disease diagnosis,evaluation of treatment strategy and prediction of prognosis.