| Objective:Corvis ST was used to study the changes of corneal biomechanics in patients with type 2 diabetes mellitus under different stages of diabetic retinopathy,and to explore the control of blood glucose and the correlation between the course of diabetes and corneal biomechanical parameters.Methods:Cross-sectional study.A total of 98 patients(179eyes)with type 2 diabetes who were examined in our outpatient clinic from August 2019 to June 2020 were divided into three groups according to the degree of diabetic retinopathy: non-proliferative diabetic retinopathy group(NDR group,n = 21),non-proliferative diabetic retinopathy group(NPDR group,n = 32)and proliferative diabetic retinopathy group(PDR group,n = 45).Thirty-six normal subjects(70 eyes)matched with sex and age were selected as the control group.Routine ophthalmological examination,computer and master optometry,measurement of random blood glucose were performed in each group,and the glycosylated hemoglobin concentration values which had been measured by endocrinology were collected,and the basic conditions such as the time of diabetes and blood glucose control were inquired.According to the slit lamp fundus examination of diabetic patients,the fundus lesions were classified,and the related ophthalmology and systemic diseases were excluded.A new visual corneal biomechanical analyzer(Corvis ST)was used to detect the subjects in each group,and the corneal biomechanical parameters were obtained.The central corneal thickness((CCT)),intraocular pressure((IOP)),first flattening time(A1T),first flattening length(A1L)and maximum deformation amplitude(HC-DA)were recorded,and the relationship between the above biomechanical parameters and the severity of diabetic retinopathy was analyzed.To study the correlation between the concentration of glycosylated hemoglobin,the course of diabetes and the parameters.Results:Along with the degree of diabetic retinopathy is aggravating,CCTS,IOP,A1 T a trend of increase gradually,HC-DA a trend of decrease gradually,until retinopathy development to PDR period,the above indicators have statistically significant differences compared with the control group(P<0.001),while A1 L value in different stages of the fundus lesions in no significant statistical difference(P > 0.05);Diabetes duration between CCT and correlation coefficient of r = 0.450,P < 0.001,a positive correlation,the correlation between IOP and coefficient of r = 0.359,P = 0.001,also a positive correlation with the duration of diabetes A1 T between the correlation coefficient of r = 0.177,P = 0.018,into a weak positive correlation,the correlation between HC-DA and coefficient of r = 0.253,P = 0.001,into a weak negative correlation,and diabetes duration and A1 L the correlation coefficient between the r =0.004,P = 0.961,There was no obvious correlation between the two.Hb A1 c %between CCT and correlation coefficient of r = 0.317,P < 0.001,both are positively related,the correlation between IOP and Hb A1 c % coefficient r = 0.259,P < 0.001,both as a weak positive correlation between Hb A1 c % and HC-DA correlation coefficient r = 0.291,P < 0.001,into a weak negative correlation,between Hb A1 c %and A1 L and A1 T correlation coefficient of r = 0.004,P = 0.960,r = 0.133,P = 0.076,there is no correlation.Conclusion:The values of CCT,IOP and A1 T in patients with advanced type 2 diabetic retinopathy were significantly higher than those in normal subjects,and CCT and IOP gradually increased with the increase of the severity of diabetic retinopathy and the prolongation of the course of diabetic retinopathy,while HC-DA decreased significantly in patients with advanced diabetic retinopathy,and decreased gradually with the increase of the duration of diabetic retinopathy and the aggravation of diabetic retinopathy.Type 2 diabetes may have a long-term effect on the cornea,and cumulative lesions and injuries may lead to changes in corneal microstructure,which have an important impact on corneal biomechanics. |
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