Decreased density of corneal basal epithelium and subbasal corneal nerve bundle changes in patients with diabetic retinopathy

PURPOSE: To define alterations in the density of corneal basal epithelium in relation to diabetic retinopathic severity and the alteration of corneal innervation using confocal microscopy. DESIGN: Prospective case-control study. METHODS: Forty-two type II diabetic patients stratified into nondiabetic (NDR), nonproliferative diabetic (NPDR), and proliferative diabetic (PDR) retinopathy and 14 age-matched healthy control subjects were studied. Epithelial and stromal cell densities and subbasal nerves were investigated by confocal microscopy. RESULTS: Corneal basal epithelial cell density (P = .0001), nerve fiber density (NFD) (P <.0001), nerve branch density (NBD) (P =.0003), and tortuosity coefficient (Tc) (P <.0001) were significantly different among the four groups. Basal epithelial density was significantly correlated with NFD (r = 0.43, P =.0009), NBD (r = 0.36, P =.007), and TC (r =-0.58, P <.0001). CONCLUSIONS: Patients with diabetes show alterations in corneal innervations and basal epithelial cell density in different retinopathic stages. We demonstrate that reduced density in basal epithelial cell is correlated with changes in innervation.