The investigators do the clinical prospective study including 30 patients with type 2 diabetes and 30 control patients without diabetes scheduled to undergo cataract surgery. The corneal endothelial cell density, variation in endothelial cell size (CV), percentage of hexagonal cells, and central corneal thickness(CCT) were recorded at baseline and at 3 months postoperatively.Then, the investigators compared the two sets of data. At last observing the change of the corneal endothelial cells in patients with type 2 diabetes after phacoemulsification with intraocular lens implantation.