Cell Density In Six Corneal Layers Of Diabetic Patients And Healthy Controls By Confocal Microscopy

Abstract

Abstract: : Purpose: To quantify cell density in six corneal layers of diabetic patients and healthy controls by in vivo confocal microscopy. Methods: The left cornea of 15 diabetic patients (NIDDM, grade of retinopathy: 20 ETDRS) and 15 healthy controls was examined with confocal microscopy. The cell density in five optical sections of six corneal layer was determined manually after full validation of the procedures. Results:The average surface cell density and standard deviation in the superficial, basal, anterior–, mid–, posterior stromal and endothelial layers was 724.8±291.3, 5950±726, 237±54, 175±36, 231±57 and 2694±322 cells·mm–2 in controls, respectively, and 815±310, 5082±427, 248±47, 198±40, 232±58 and 2655±385 cells·mm–2 in diabetics, respectively. In both groups, the mid–stromal density was significantly lower than in the anterior or posterior stromal layers (P<0.025). Surprisingly the difference between diabetics and controls was significant in the basal epithelial layer (–14.6%, p<0.001) and in mid–stroma (+13.1%, p<0.029). Conclusions: The lower cell density in the mid–stroma of both groups can be attributed in part to differences in oxygen concentration in the stromal layers. The lower basal epithelial and the higher or equal superficial cell densities in diabetics compared to controls suggest a longer turnover time of the superficial cells or a shorter turnover time of the basal epithelial cells in diabetes. The higher mid–stromal density may be attributed to a higher glucose concentration in the cornea of diabetics.

Keywords: cornea: epithelium • cornea: endothelium • cornea: stroma and keratocytes