Xuzhou Medical University Xuzhou 221002 Jiangsu Province China;
Department of Ophthalmology Affiliated Hospital of Xuzhou Medical University Xuzhou 221002 Jiangsu Province China;
Xuzhou Medical University Xuzhou 221002 Jiangsu Province China;
Department of Ophthalmology Affiliated Hospital of Xuzhou Medical University Xuzhou 221002 Jiangsu Province China;
type 2 diabetes; retinopathy; ocular surface; corneal nerve; in vivo confocal microscopy;