| BackgroundDiabetes can lead to a variety of eye complications,such as diabetic retinopathy,cataract,glaucoma,keratopathy,refractive changes,oculomotor nerve palsy,and chronic eyelid inflammation.Corneal lesions include dry eye disease,corneal erosion,persistent epithelial defects,and even visual-threatening corneal ulcers.The corneal epithelial layer is a physical barrier against the invasion of external pathogenic factors.The maintenance of its integrity depends on the connection between adjacent cells and the basement membrane as well as the continuous self-renewal of epithelial cells.Diabetes can cause changes in the basal cells and membrane of the corneal epithelium,leading to the loss of basal epithelial cells,corneal epithelial lesions and adhesion disorders.In addition to abnormal corneal epithelium and decreased innervation,diabetes can also cause changes and damage to limbal stem cells and conjunctival goblet cells.In order to further verify the small changes in cornea caused by diabetes,the present study used anterior segment OCT to measure the thickness of central corneal epithelium,limbal epithelium and bulbar conjunctival epithelium to evaluate the effect of diabetes on the ocular surface epithelium.MethodPatients with type 2 diabetes diagnosed in the inpatient department and outpatient department of endocrinology department of zhujiang hospital of southern medical university from November 2019 to January 2020 were selected as the observation group,while non-diabetic patients and normal patients with no difference in age and gender were selected as the control group.The observation group included 34 patients with 67 eyes,and the control group included 32 patients with 64 eyes.According to the presence or absence of dry eye,the diabetes group was divided into the dry eye group and the non-dry eye group.The control group was divided into dry eye group and non-dry eye group.Exclusion criteria for the normal participants included history of any ocular pathology,surgery and contact lens wear.Gender,age,course of diabetes,fasting glucose concentration and glycosylated hemoglobin were recorded.The OSDI score questionnaire,fluorescein tear film break-up time(BUT),assessment of ocular surface staining with fluorescein(quantified using the Oxford scheme)score,total meibomian gland loss score,central corneal epithelial thickness(CET),upper,lower,nasal,temporal and marginal limbal epithelial thickness(LET),and bulbar conjunctival epithelial thickness(BET)in the corresponding position were investigated,meibomian gland absence score,central corneal epithelial thickness,limbal corneal epithelial thickness and bulbar conjunctival epithelial thickness.Non-parametric test was used to compare the above indicators in the two groups through SPSS.Spearman correlation coefficient was used to analyze the correlation between ocular surface epithelial thickness and clinical parameters.P<0.05 was considered statistically significant.Result1.Compared to the control group,BUT was significantly shorter(P<0.001),FLScore was significantly higher(P<0.001)and meibomain gland deletion score was significantly higher(P<0.001)in type 2 diabetes.There was no significant difference in OSDI score between the two groups(P>0.05).2.Compared to control subjects,mean CET was significantly thinner(P=0.001),mean LET was significantly lower(P=0.010)and mean BET was significantly thinner(P=0.013)in the type 2 diabetes group.3.In type 2 diabetes group,the LET was had a significantly thinner in the inferior(P=0.006),but not in the superior(P=0.404),nasal(P=0.079)and temporal regions(P=0.078)as compared to control subjects.In addition,type 2 diabetes had a significantly thinner BET in the inferior(P=0.001),but not in the superior(P=0.326),nasal(P=0.062)and temporal regions(P=0.194)as compared to control subjects.4.In type 2 diabetes group,HbA1cwas correlated with Oxford score(R=0.246,P=0.045).The nasal BET was correlated with meibomian gland absence score(R=-0.265,P=0.030).OSDI was correlated with CET(R=-0.299,P=0.014).5.In all dry eye patients,compared to control subjects,CET was significantly thinner(P<0.05),but there was no significantly difference in the mean LET and BET(P>0.05).6.In all non-dry eye patients,compared to control subjects,there was no significantly difference in the CET(P>0.05),but the mean LET and BET was significantly thinner(P<0.05).ConclusionThe thickness of central corneal epithelium,limbal corneal epithelium and bulbar conjunctival epithelium in diabetic patients were significantly thinner,and the thickness of the epithelium was not correlated with fasting blood glucose,hba1c and the course of disease.Ocular surface epithelial thickness may be used as an indicator for clinical monitoring of ocular surface conditions.SD-OCT can not only improve our understanding of ocular surface diseases,but also be a valuable tool for clinical evaluation of ocular surface epithelium. |
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