Effect Of Diabetes Mellitus On Tear Film And Keratoconjunctival Epithelium

1.BackgroundThe pathogenic factors of diabetes mellitus, such as hyperglycemia, absolute or relative hypoinsulinemia, hyperglucagonemia, hyperlipidemia, and so on, would induce several kinds of chronic complication. It is generally accepted that hyperglycemia leads to retinal micro-angiopathy, variation of blood components and change of blood rheology is fundamental pathogenesis of diabetic retinopathy (DR). A few study described that diabetes would result in tear film and keratoconjunctival epithelium alteration, such as decreasing of basal tear secretion, increasing of squamous metaplasia grade, and reducing of goblet cell density etc. There is not a comprehensive research which describes the relationship between hyperglycemia and the changes of tear film and keratoconjunctival epithelium, the association between the duration, the severity of diabetes and the alteration of tear film and keratoconjunctival epithelium. This study aimed to represent the connection between the diabetic duration, the severe extent of diabetes, the grade of diabetic retinopathy and the changes of tear film and keratoconjunctival epithelium by analyzing the consequence of fluorescein vital staining, tear film break up time (BUT), Schirmer's-I test,conjunctival impression cytologic analysis, ftmdus fluorescein angiography between diabetes and healthy control subjects. 2. Subjects and methods.2.1 ParticipantsOne hundred and eight eyes of fifty-four patients with noninsulin-dependent diabetes mellitus aged between 50 and 94 years (mean, 66.26 years) as well as sixty eyes of thirty healthy subjects aged from 26 to 80 years (mean, 64.23 years) were recruited from Zhejiang Hospital from January 1998 through March 2001. Those diabetes were divided into different groups according to diabetic control condition and diabetic duration.2.2 ExaminationVisual acuities were obtained and ocular fundus and slit lamp microscope examinations were carried out in either of the two group subjects.The diabetes mellitus and control subjects underwent examinations including tear film break-up time and fluorescein vital staining (standardized fluorescein strip), Schirmer's-I test (standardized strip of filter paper), and conjunctival impression cytologic analysis (Millipore GS, 0.22um, strip of cellulose acetate filter paper). The standard Schirmer's-I test was performed with topical anesthesia. The standardized strips of filter paper were placed in outer canthus of lateral eyelid for five minutes with the eye closed. The impression cytologic specimens were obtained from temporal bulbar conjunctiva adjacent to the corneal limbus after administration of topical anesthesia, then fixed with 95% alcohol, stained with PAS and hemotoxylin (periodic acid-schiff), and finally coverslipped. The studies of the grade of conjunctival epithelial squamous metaplasia and the quantity of conjunctival goblet cells were conducted by pathological photographs analysis and study system. The diabetes was evaluated byfluorescein angiography.The records of fluorescein vital staining were scored from zero to nine. The interval between the last complete blink and appearance of the first corneal black spot in the stain tear film was measured three times, and the mean value of measurements was calculated as the value of BUT. Each value of Schirmer's-I test was reported by the length of wetting filter paper. The impression cytologic specimens were assigned different grades of conjunctiva! epithelial squamous metaplasia according to Nelson's grading scheme. The goblet cells densities of the specimens were also reported as cells per square millimeter.2.3 Statistical AnalysisData were processed by SPSS 10.0 software. All data were recorded as X盨.Each group data were analyzed by Chi-Square Test, Student's Unpaired T Test, Wilcoxon Rank Sum Test and One Way ANOVA Test.3. ResultsThere were no age-related (Student's Unpaired T Test, P>0.()5) and gender-related (Chi-Square Test, P>0.05) statistical differences between patients with diabetes and contr...