Correlation Between Corneal Thickness And Corneal Endothelial Cell Morphology In Type 2 Diabetic Patients

Objective By observing the changes of corneal thickness and corneal endothelial cell morphology in patients with type 2 diabetes mellitus,to explore the influence of diabetes mellitus on corneal related parameters,so as to provide the basis for corneal assessment in diabetic patients before ophthalmic surgery.Methods Select the patients aged 55-75 years old without obvious corneal lesions,who came from the ophthalmic clinic of the General Hospital of Ning Xia Medical University in Nov,2018 to Dec,2019.According to the history of diabetes or not,patients were divided into case group and control group including 60 cases(117 eyes)in case group and 58 cases(116 eyes)in control group.To explore the influence of fundus staging on corneal parameter,we divided the diabetic patients into the two groups:1 group(non-proliferative disease group,60 eyes)and 2 groups(proliferative disease group,57 eyes),who performed fundus photography,fundus examination and fundus fluorescence angiography to determine whether there was neovascularization or vitreous hemorrhage.Additionally divided the case group patients into group A(5-year ≤ group A < 10 years,34 eyes),group B(10-year ≤group B < 15 years,36 eyes),and group C(group C ≥ 15-years,47 eyes)with course of disease.In addition to routine examination,all enrolled patients were measured by noncontact Specular Microscope including endothelial cell density(ECD),percentage of hexagonal cell(HEX),variation coefficients(CV),and central corneal thickness(CCT)byultrasonic corneal thickness meter.After all,collect data and make statistical analysis on the data.Results 1.The values of ECD and HEX in the case group were significantly lower than those in the control group(P < 0.001),while the values of CV and CCT in the case group were higher than those in the control group(P < 0.001).2.Compared with the control group,the values of ECD and HEX in the non-proliferative and proliferative patients were significantly reduced(P < 0.001),while the values of CV and CCT were significantly increased(P < 0.001).In the case group,the values of ECD and HEX in proliferative stage were lower than those in non-proliferative stage(P <0.05),while the values of CV and CCT in proliferative stage were higher than those in non-proliferative stage(P < 0.05).3.Compared with the control group,except that there was no statistical difference in CCT values between the two groups,the ECD and HEX values of group A,group B and group C were all reduced,while the CV and CCT values were all increased(P < 0.05).The comparison results of ECD values between groups A,B and C were > in group A,B in group B,and C in group B(P < 0.05).Among the three groups,CV only showed difference between group A and group C(P < 0.05).There were differences in HEX between group A and group B and between group A and group C(P < 0.05).There was no significant difference in CCT results between the three groups.4.There was a positive correlation between corneal CCT and CV in diabetic patients(r=0.195,P < 0.05),and there was no significant correlation between corneal CCT and ECD and HEX(P > 0.05).ECD was positively correlated with HEX(r=0.326,P < 0.01),ECD was negatively correlated with CV(r=-0.520,P < 0.01),and CV was negatively correlated with HEX(r=-0.276,P < 0.01).Conclusion Type 2 diabetes affects corneal endothelial cell density,hexagon cellratio,coefficient of variation,and corneal thickness in patients.Compared with the control group,the corneal endothelial cell density and the proportion of hexagon cells decreased,while the coefficient of variation and corneal thickness increased.Meanwhile with the extension of the disease and the aggravation of diabetic retinopathy,the corneal endothelial cell density and the proportion of hexagon cells decreased significantly,while the coefficient of variation and corneal thickness increased significantly.Corneal thickness is positively correlated with the coefficient of variation in diabetic patients,and corneal thickness can reflect the changes of corneal endothelium.Therefore,we suggest that diabetic patients should be tested and evaluated for corneal endothelial cells and corneal thickness before eye surgery,and pay attention to the protection of corneal endothelial cells during operation to reduce postoperative corneal complications.