Correlation Analysis Of Inner Structure Of Macular Area With Visual Acuity And Surgical Prognosis In Patients With Idiopathic Epiretinal Membrane

Purpose:In this study,spectral domain optical coherence tomography(SD-OCT)was used to observe the changes of OCT fine structure in idiopathic epiretinal membrane(ERM)patients,and the correlation between the inner structure of macular area and visual acuity and surgical outcome was analyzed.Methods:Collected from September 2018 to June 2020 The First Affiliated Hospital of Dalian Medical University ophthalmology in patients with idiopathic ERM,a total of 49 people(55 eyes),including 19 people(19 eyes)surgical patients,all vitrectomy surgery patients underwent 25 G vitrectomy combined with macular anterior membrane and internal limiting membrane removal,and cataract phacoemulsification and intraocular lens implantation were performed simultaneously in patients with cataract.A retrospective analysis was carried out on the above.All patients received slit lamp microscopy,direct ophthalmoscopic examination,fundus photography,SD-OCT examination,intraocular pressure and best corrected visual acuity(BCVA).BCVA was converted into logarithmic visual acuity with minimum resolution Angle(Log MAR)for statistical analysis.The ERM was divided into four stages according to the SD-OCT.The macular area all quantitative measurements and qualitative assessments were made.The central foveal thickness(CFT),ectopic inner foveal layer(EIFL),inner nuclear layer(INL),outer nuclear layer thickness(ONL),choroid thickness,outer membrane integrity,ellipsoidal zone integrity,cotton ball sign and ERM stage were measured and recorded.Finally,the correlation between each parameter of OCT and BCVA before and after surgery,as well as the correlation with surgical prognosis were analyzed.Results :Preoperative data analysis of all patients:Preoperative data of BCVA showed no statistical significance except between ERM stage I and stage Ⅱ and Ⅲ(P>0.05),the rest were statistically significant(P<0.05);There was no statistical significance between stage Ⅱ and stage Ⅲ in CFT(P>0.05),and there was statistical significance among other stages(P<0.05);There was no statistical significance in EIFL between stage I and stage Ⅱ(P>0.05),the others were statistically significant(P<0.05);There was no statistical significance between stage Ⅱ and stage Ⅲ and stage Ⅳ in ONL(P>0.05),the rest were statistically significant(P<0.05);There was no significant difference in INL and choroidal thickness(P>0.05),the integrity of the outer membrane and the ellipsoid band had no statistical significance(P>0.05),and there was statistical significance in cotton ball sign in each period(P<0.05).Stages were significantly positively correlated with CFT,INL,EIFL,ONL and preoperative BCVA(P<0.05),preoperative BCVA(Log MAR)was statistically significant and positively correlated with EIFL,CFT,stage,outer membrane integrity and ellipsoid band integrity(P<0.05),the other indicators ONL,INL,cotton ball sign and choroidal thickness had no statistical significance(P>0.05).The independent variables EIFL,ONL and dependent variable CFT were put into the model for multiple linear regression analysis.The partial regression coefficient of EIFL was 0.72,while that of ONL was 0.40,CFT=0.72×EIFL+0.40×ONL+164.9.With preoperative BCVA as the dependent variable and OCT parameters as the independent variable,a multiple linear regression model was established.The model was established as preoperative BCVA(Log MAR)=0.76×the integrity of the external membrane-0.32 ×choroidal thickness-0.73×EIFL-0.043.Data analysis results of the surgical eyes:There were no significant differences in BCVA,CFT,EIFL,ONL,INL and choroidal thickness among stage Ⅱ patients(P>0.05),BCVA,CFT,EIFL and ONL were significantly different in stage Ⅲ patients(P<0.05),there was no significant difference in INL and choroid thickness(P>0.05),BCVA,CFT and ONL in stage Ⅳ patients were statistically significant(P<0.05),EIFL,INL,choroidal thickness,the integrity of the outer membrane,ellipsoid and the cotton ball characteristics was no significant difference(P>0.05).There were significant differences between postoperative BCVA and preoperative BCVA,EIFL and ONL(P<0.05),and had no significant difference with CFT,INL,integrity of outer membrane,integrity of ellipsoid and cotton ball characteristic(P>0.05),and the multiple linear regression analysis model of BCVA as the dependent variable found that there were significant differences in BCVA and EIFL before surgery(P<0.05),there was no significant difference in the rest(P>0.05).The partial regression coefficient of preoperative BCVA was 0.58,and EIFL partial regression coefficient was-0.87.The model equation was obtained as follows: postoperative BCVA=0.58×preoperative BCVA-0.87×EIFL-0.09.Conclusion:1.Nonoperative and preoperative eye analysis:1.1 The stage is closely related to the inner retinal structure and visual acuity.The higher the stage,the thicker the CFT,EIFL,INL and ONL,and the worse the preoperative visual acuity,which confirms the ERM stage.1.2 Visual acuity of ERM patients is jointly determined by the inner and outer retinal structures.The thicker EIFL and CFT,the more incomplete the outer membrane and ellipsoid band,and the worse the preoperative visual acuity.1.3 The incidence of cotton ball sign increased with the increase of stage,and it was not found that cotton ball sign could directly affect vision.2.Data analysis of the surgical eyes:vitrectomy combined with macular membrane and internal boundary membrane removal can effectively improve the visual acuity of ERM patients,and the thickness of EIFL in ERM is the influencing factor of visual acuity prognosis.The thicker EIFL,the worse the postoperative visual acuity,the worse the prognosis.The lower the stage,the better the postoperative visual acuity.Stage Ⅱ ERM is the best time for surgery.