A Preliminary Study Of Tear Secretion And Tear Film Function In Type 2 Diabetic Patients

Objective:To study tear secretion and tear film function in type 2 diabetic patients and compare outcomes of different diabetic retinopathy in type 2 diabetes mellitus.To establish rapid and reliable methods to screen and detect tear function in diabetic patients.Methods:25 diabetic patients with non-proliferative diabetic retinopathy(NPDR),25 diabetic patients with proliferative diabetic retinopathy(PDR) and 25 healthy persons as control group were included. All examined with tear break up time(BUT), Schirmer I test(SIt),rose bengal(RB) staining.The general datas including patients age,gender,duration of diabetes mellitus,history of diabetic treatment,vision acuity,slit-lamp examinations and indirect funduscopy,et al. Every diabetic patients were done with fundus fluorescein angiography (FFA).13 patients with NPDR,12 patiens with PDR and 12 controls were performed with total tear proteins detection.11 patients with NPDR,15 patiens with PDR and 15 controls were performed with tear proteins sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).Still 36 diabetic patients with NPDR,33 diabetic patients with PDR and 34 healthy persons as control group were performed with corneal fluorescein staining and TMS-4 corneal topography examinations.The indices of the latter were usde to evaluate cornea surface regularity.Results:1. Compared to NPDR group and control group,the values of BUT and SIt were decreased in PDR group(P<0.01);the positive rate of RB staining was increased in PDR group(P<0.05 and P<0.01,respectively).Compared to control group ,NPDR group had a significant reduction in SIt(P<0.01),but had no significant differences in the value of BUT and the positive rate of RB staining(P>0.05).2. There was no difference in total tear proteins amount.But Compared to control group,PDR group had a significant reduction in lysozyme, lactoferrin and tear specific prealbumin concentration(P<0.01); Compared to NPDR group,PDR group had a significant reduction in lysozyme,lactoferrin(P<0.05) and tear specific prealbumin concentration (P<0.01) .There is no differences in lysozyme, lactoferrin and tear specific prealbumin between NPDR group and control group(P>0.05).3. The SRI and SAI were significantly elevated in patients both with PDR and NPDR,compared to that in normal subjects(P<0.01),espacially in patients with PDR.There is no significant differences in the amount of astigmatism and the average corneal refractive power between diabetic patients and normal subjects(P>0.05).Corneal fluorescein staining scores were higher in patients with PDR and NPDR,compared to that in normal subjects(P<0.01),especially in patients with PDR.In diabetic patients,the SRI and SAI were positively correlated with fluorescein staining scores(Spearman's r=0.754,0.480, P<0.01)Conclusions:1. Tear film function in type 2 diabetic patients presented significantly abnormal.The changes were more significant in diabetic patients with PDR.In our clinic work,we should not ignore some complications due to dysfuction of tear film.2. Traditional examinations for testing function of tear film have some shortcomings. SDS-PAGG is a reliable tool to find the tear abnormalities in diabetic patients.In this way,proteins in tear,such as the reduction of lysozyme, lactoferrin and tear specific prealbumin concentration are sensitive indices for diagnosis.3. Diabetic patients with dysfunction of tear film have an irregular corneal surface that may contribute to their abnormalities of ocular surface.The SRI and SAI could be used as rapid and reliable diagnostic indices for diabetic patients dysfunction of tear film as well as for evaluating the severity of this abnormality.