A Clinical Study Of Optical Coherence Tomography Angiography To Observe The Vascular Density And Retinal Nerve Fiber Layer Thickness In The Macular Area Of Myopia And Analysis Of Related Factors

Objective: The purpose of this study is to use optical coherence tomography angiography(OCTA)to measure and compare macular vascular density,ganglion cell complex(GCC)thickness and peripheral nerve fiber layer thickness(RNFLT)in patients with different refractive states.And compare their relationship with the axial length(AL)and vascular density(VD).Methods:Methods used in this paper is a cross-sectional observational study.The included subjects were 80 eyes of 139 patients who were diagnosed as myopia or high myopia(HP)from October 2019 to August 2020 at Qingdao Municipal hospital Eye Center.Among them,79 eyes of 44 patients were in the experimental group(≥6.00 D or AL≥26mm)60 eyes of 41 were in a Control group.Microvessel density of macular area and optic disc was collected by OCTA,and superiorficial 、 deep layers and choriocapillaris of macular area 、Ganglion Cell Complex thickness and Retinal nerve fiber layer thickness were obtained automatically.Statistical analysis was carried out according to SPSS 22.0 statistical software,χ±S represents the measurement data in this experiment,and the results of classification variables are expressed in N(%).Two independent sample t-tests were used for the comparison of measurement data between groups,and the χ2 test was used for the comparison of categorical variables between groups.Pearson correlation was used in the correlation analysis between the variables.P<0.05 indicates that the difference is statistically significant.Graphpad prism 8.0 software is used to draw the scatter chart and histogram.Results:1.There was no statistical difference in age and gender between the two groups.2.Compared the experimental group with the control group,there are differences in parafoveal superficial vascular density(SVD),perifoveal area SVD,parafoveal deep vascular density(DVD),perifoveal area DVD,and choriocapillaris vascular density(CCVD).There is statistical significance(both P<0.05),but the foveal SVD and DVD are not statistically significant(P=0.552,P=0.752).3.The difference in foveal blood flow density(FD)within a width of 300 microns around the FAZ area was statistically significant between the two groups(P<0.05),but there was no significant difference in the foveal avascular area(FAZ)and the perimeter of the foveal avascular area(PERIM)between the two groups(P=0.614,P=0.132).4.The average thickness of GCC,the thickness of the superior hemi of GCC,the thickness of the inferior hemi of GCC,and the general loss volume(GLV)of GCC are statistically different between the two groups,(P<0.05).There was no significant difference in local loss volume(FLV)of GCC between the two groups(P=0.078).5.The difference between the experimental group and the control group was statistically significant between the RNFLT around the optic disc,the thickness above the RNFL,the thickness on the temporal side of the RNFL,and the thickness on inferior side of the RNFL(P<0.05).There was no significant difference in the thickness on the nasal side of the RNFL between the two groups(P=0.602).6.Parafoveal SVD was negatively correlated with AL(P<0.05,r=-0.279),positively correlated with the average thickness of GCC(P<0.05,r=0.303),and positively correlated with RNFLT around the optic disc(P<0.05,r= 0.231)and there is no correlation between parafoveal SVD and FAZ(P=0.068,r=0.164).7.Parafoveal DVD was negatively correlated with AL(P<0.05,r=-0.209),positively correlated with the average thickness of GCC(P<0.05,r=0.204),and positively correlated with RNFLT around the disc(P<0.05,r= 0.181),while the parafoveal DVD has no correlation with FAZ(P=0.211,r=0.117).8.CCVD was negatively correlated with AL(P<0.05,r=-0.248),and negatively correlated with RNFLT around the disc(P<0.05,r=-0.341).There is no correlation between CCVD and average thickness of GCC and FAZ(P=0.890,r=-0.013;P=0.236,r=-0.107).9.AL is negatively correlated with the average thickness of GCC(P<0.05,r=-0.428),and AL is negatively correlated with RNFLT around the disc(P<0.05,r=-0.278).Conclusion:1.Compared with the control group,patients in the high myopia group had significant differences in the SVD and DVD in parafovea,perifoveal area,and CCVD,but no significant differences were seen between the SVD and DVD in macular fovea.That is,except for the fovea,high myopia patients have lower blood vessel density than normal myopia people.2.Although there was no statistically significant difference in FAZ between the two groups,the FD of the high myopia group was significantly lower than that of the control group.3.Except for the nasal side,RNFLT around the disc and each quadrant of the high myopia patients was reduced compared with the control group.Compared with the control group,the average GCC thickness and GLV of the high myopia group were statistically significant.4.Except for the nasal side,the thickness of the nerve fiber layer around the disc and each quadrant of the high myopia patients was reduced compared with the control group.Compared with the control group,the average GCC thickness and GLV of the high myopia group were statistically significant.