[Distribution and morphological changes of corneal nerves in type 2 diabetic patients detected by confocal...

To evaluate corneal nerve distribution and morphological changes in subjects with type 2 diabetes.

Sixty-five eyes of 59 patients with type 2 diabetes (26 males, 39 females) and 26 eyes (10 males, 16 females) of control subjects were included in the present study. Based on the indirect ophthalmoscopic examination and fluorescein angiography, the diabetic group was divided into three sub-groups according to the stage of retinopathy: without diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). The central cornea was scanned with Confoscan 3.0. The images of subbasal nerve plexus and stromal nerves were analyzed.

Corneal branch nerve fiber density of subbasal nerve plexus decreased in diabetic group as compared with control group, the difference was statistically significant. The decrease of nerve fiber density appeared only in the PDR sub-group, while the decrease was not significant in NDR and NPDR sub-groups. No obviously difference was found among control group, NDR and NPDR sub-groups. The proportion of patients with an abnormal morphologic nerve fibers in mid-stroma in diabetes group was greater than that in the control group and the difference was statistically significant (chi(2) = 46.613, P = 0.000).

Corneal confocal microscope allows rapid and noninvasive in vivo evaluation of corneal nerves. The subbasal and stromal nerves of subjects with type 2 diabetes were abnormal in morphology.