| Objective:As a main complication of diabetes mellitus(DM),diabetic retinopathy(DR)is one of the leading causes of blindness and visual impairment in the working-age population around the world.Diabetic macular edema(DME)is The most common complications of DR can lead to severe vision loss in patients.Therefore,early intervention therapy for DR patients is of particular importance for slowing down the progression of DR and preventing loss of vision.In this paper,the differences of optical coherence tomography angiography(OCTA)in normal,DM,and DR patients with macular fovea non-perfusion region(Foveal avascular zone,FAZ),retinal vessel density and thickness were compared.The same method was used in DR patients to study the differences in parameters related to DME patients and No-DME patients and to analyze the related factors affecting the visual acuity of DR patients.Methods:Observational cross-sectional study.586 eyes of 304 subjects met the conditions of this study(38 normal subjects(66 eyes),266 T2MD patients(89 DR subjects(92 eyes),177 NO DR subjects(175 eyes)).All subjects underwent medical history collection,binocular color fundus photography,non-contact intraocular pressure(NCT),best corrected visual acuity(BCVA),EDTRS visual acuity test,the fund fluorescein angiography(FFA)was performed on patients with macular edema and severe diabetic retinopathy with NPDR stage and above.Subjects performed OCTA examination after full mydriasis to obtain high-definition scan images in the macular area of 6.00mm x 6.00mm size.Deep vessel density(DVD)and superficial vessel density(SVD),and the six layers of the membrane thickness(Full,Inner,Outer,ILM-BRM,OPL-BRM,ISOS-BRM);Full-layer retinal FAZ area,A-circularity index index(AI),perimeter(PERIM)and the 300 micron width Foveal Density(FD)were obtained by the built-in analysis software,and were compared with the normal human eyes.Patients with DR were divided into two groups according to whether there was DME or not.At the same time,the correlation of these parameters on visual acuity was analyzed by univariate and multivariate analysis.Measurement data were expressed as mean±standard deviation(x±s),count data were expressed as frequency(composition ratio),and t-test,chi-square test,Pearson correlation analysis,multiple linear regression analysis and other statistical analysis were performed.Results:A total of 304 subjects were enrolled in the study.275 eyes were excluded due to refractive error,poor patient coordination,and other factors that caused the image quality to fall below the study requirements.Finally,we selected 333 eyes from 184 subjects to carry out data analysis,it included 66 healthy eyes,175 T2MD non-DR eyes,and 92 DR eyes(24 eyes were mild NPDR,18 eyes were moderate NPDR,36 eyes were severe NPDR,and 14 eyes were PDR);among the DR patients,25 eyes were CSME(1 eye was mild NPDR,17 eyes were severe NPDR and 7 eyes were PDR),and NO-DME 67 eyes.Part Ⅰ Comparison of groups of Normal,DM and DRIn the Normal,DM,and DR groups,the number of EDTRs visual acuity tables and FD scores gradually decreased as the disease progressed(EDTRs:86.32±2.88,82.15±7.05,69.90±13.62,P<0.001;FD:52.22±4.76,49.94±5.37,44.85±6.19,P<0.001);There was no statistical difference between the normal group and’ the DM group in FAZ and AI(FAZ:0.325±0.117、0.313±0.099,P=0.84;AI:1.09±0.03、1.11±0.09,P=0.098),the FAZ and AI values in the DR group were significantly higher than those in the other two groups(0.450±0.27,P<0.001;1.22±0.15,P<0.001).The whole image,parafovea,and perifovea of SVD showed no difference in the normal and DM groups(whole image:46.76±3.64、46.54±3、58,P=0.968;parafovea:47.80±5.16、47.56±4.81,P=0.983;perifovea:47.69±3.65、47.45±3.70,P=0.956),but significantly reduced in DR group(whole image:41.65±4.75,P<0.001;parafovea:41.71±6\03,P<0.001;perifovea:42.37±4.93,P<0.001);there’s no significant difference in the three groups of fovea(16.07±6.46、16.03±6.40、14.54±7.68;P=0.199)。In DVD,the mean values of three groups of whole image(45.27±4.36、45.23±4.70、42.42±4.88)was in group NORMAL>DR,DM group>DR group,the difference was statistically significant(P<0.001),and the other two groups had no statistical significance(P=0.948).The fovea mean values(32.18±8.03、32.20±7.48、26.39±9.30)was in group:NORMAL>DR,DM>DR,the difference was statistically significant(P<0.001),and the other two groups had no statistical significance(P=1.000);the mean values of parafovea(52.18±3.83,51.80±4.23,47.48±5.93)in the NORMAL group>DR group,DM group>DR group,the difference was statistically significant(P<0.001 for all),and the other two groups were not statistically significant(P=0.881);The mean values of perifovea(46.19±4.95,45.96±5.22,43.44±5.22)in the NORMAL group>DR group,DM group>DR group,the difference was statistically significant(P<0.001 for all),the other two groups were not statistically significant(P=0.763).The ISOS-BRM of macular area in the three groups showed NORMAL>DM>DR(60.09±1.77,59.31±2.83,53.52±8.05),and the difference was statistically significant(P values were 0.033,<0.001,<0.001,respectively).There was no significant difference in the thickness of the inner retina between the three groups;the other four layers showed a significant increase in the DR group compared with the other two groups(P<0.001 for all),and there was no significant difference between the DM and the Normal group(P>0.05).Part Ⅱ Comparison of NO-DME patients and DME patientsIn the DR group,the average EDTRs in the NO-DME group were greater than those in the DME group(74.72±10.27、57.00±13.26;P<0.001);the average AI of patients in the DME group is greater than that of the NON-DME group(1.27±0.13、1.21±0.15;P=0.048);There was no significant difference in the mean values of FAZ and FD between the two groups(P all>0.05).The mean value of fovea in patients with DME in SVD is greater than that in NO-DME group(19.38±7.9、12.73±6.81;P<0.001);The other parameters were not different between the two groups(P>0.05).In DVD,the average parafovea of patients in group NO-DME was larger than that in group DME(48.36±5.81、45.13±5.7;P=0.019);the other parameters were not statistically different between the two groups(P>0.05).The thickness of full retina in group DME was larger than that in group no-DME in all regions(fovea:418.32±152.96、253.46±27.81,P<0.001;parafovea:415.58±78.48、327.86±24.71,P<0.001;perifovea:357.21±50.76、297.20±31.09,P<0.001);for the ISOS-BRM layer,the thickness of the different regions of the NO-DME group was larger than that of the DEM group(fovea:56.19±6.09、46.36±8.41,P<0.001;parafovea:56.88±4.49、50.72±6.24,P<0.001;perifovea:55.73±3.83、52.55±4.10,P<0.001)。The thickness of retina in each area of the remaining layers was greater in the DME group than in the NO-DME group(P<0.001 for both).Part Ⅲ Correlation analysis of various factors and visual acuityIn the correlation analysis of visual acuity in DR patients,it was found that AI was negatively correlated with vision(r=-0.227,P=0.029);FD is positively correlated with vision(r=0.275,P=0.008);DVD fovea is positively correlated with vision(r=0.281,P=0.007).And a negative correlation was found between the visual acuity and the thickness in fullfove(r=-0.452,P<0.001)and outerfovea(r=-0.470,P<0.001)and ILMfove(r=-0.450,P<0.001)and OPLfovea(r=-0.370,P<0.001);only ISOS-fovea thickness is positively correlated with vision(r=0.637,P<0.001).Conclusion:1.OCTA is an important tool in screening and follow-up of diabetic patients,and can detect subclinical structural changes.2.DR is a disease with multiple risk factors affecting each other.Hypertension,coronary heart disease,course of disease and smoking all have an impact on it.3.The appearance of DME can aggravate visual impairment in patients with DR and change the structure of the retina.4.The visual acuity of patients with DR is related to multiple factors.After further multiple linear regression analysis,it was found that the thickness of DVD and ISOS in macular area is an important indicator affecting the visual acuity of patients,and the influence of ISOS thickness is greater,which indirectly reflects the progress of the disease.We should pay more attention to these two indicators in clinical research and treatment. |
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