Objective: To test the changes of corneal sensation in diabetic patients and to observe the diabetic corneas using confocal microscopy.
Methods: One hundred and thirty-two diabetic patients were enrolled in this study. The diabetic history and medication were recorded. The FBG and HbA(1c) were checked for every patient. The patient's eye was systemically checked, including the IOP, visual acuity, cornea sensation, lenses, and the fundus. Two hundred patients of other diseases were enrolled as controls. The cornea of 85 patients and 56 controls were checked by the confocal microscopy. The right eyes of both patients and controls were used for analysis.
Results: The cornea sensation of diabetic patients was significantly depressed as compared to that of the controls (P < 0.01). The depression of cornea sensation was related to the course of the disease, the presence of diabetic retinopathy and the degree of the diabetic retinopathy (P < 0.05). The confocal microscopy revealed that there was a higher corneal epithelium edema rate (11.76%) in diabetic patients than that of the controls (1.79%) (P < 0.05). The nerve fiber density of the diabetic patients was decreased and there were some morphological changes in the nerve fiber of diabetic patients, such as sparse, slim, less branches, less long fibers, edema and zigzag of the fibers.
Conclusion: The depression of the corneal sensation in diabetic patients is probably caused by the reduction and the degeneration of the corneal nerve fibers.