AIM:To evaluate the changes of corneal endothelium after phacoemulsification in diabetic patients with cataract and simple cataract.

METHODS: A total of 92 eyes of 78 patients with cataract were diagnosed from October 2016 to June 2017 in People's Hospital of Guangxi Zhuang Autonomous Region. Two groups were divided into diabetic group and non-diabetic group according to whether there was diabetes or not. The diabetes group had 40 patients(44 eyes)and non-diabetes group had 38 patients(48 eyes). All patients were performed phacoemulsification combined with intraocular lens implantation by an experienced ophthalmologist. And then, corneal endothelial density(CED), hexagonal cell percentage(HCR), coefficient of variation(CV)and central corneal thickness(CCT)were detected by non-contact corneal endothelium count instrument before surgery and 1, 4 and 8wk after surgery. Meanwhile, the morphology of corneal endothelium was detected by confocal microscope before surgery and 4 and 8wk after surgery. And the occurrence of intraoperative floppy iris syndrome in the two groups was observed respectively.

RESULTS: Compared with non-diabetes group, the preoperative percentage of hexagonal cell in diabetes group was decreased, the coefficient of variation was increased, the differences were statistically significant(P<0.05); but there were no significant difference in corneal endothelial density and central corneal thickness(P>0.05). Compared with non-diabetes group, the postoperative percentage of hexagonal cell in diabetes group at different time points was decreased, coefficient of variation was increased, the differences were statistically significant(P<0.05),the difference in corneal endothelial density and central corneal thickness were not statistically significant(P>0.05). Compared with pre-operation, the percentage of hexagonal cell and corneal endothelial density in diabetes group and non-diabetes group at postoperative 1,4 and 8wk were decreased obviously, coefficient of variation was further increased, there were statistical difference(P<0.05); the central corneal thickness at postoperative 1wk was obvious incrassation, there was statistical difference(P<0.05), but there was no significant difference in the central corneal thickness at postoperative 4 and 8wk(P>0.05); comparison of the morphology of corneal endothelium at pre-operation and the morphology of corneal endothelium at postoperative between two groups, the preoperative heteromorphism of morphology of corneal endothelium in diabetes group was obvious, size of a pleomorphic endothelial cell was different; at postoperative 4wk, the heteromorphism of morphology of corneal endothelium was further obviously and so was size of cell body, we could see the big nucleus; at postoperative 8wk, morphology of corneal endothelium in diabetes group recovered more slowly, we still saw many irregular endothelium and large nucleus. The incidence of intraoperative floppy iris syndrome in the diabetic group was 14%, and the non-diabetic group was 0.

CONCLUSION: Diabetes and phacoemulsification can damage corneal endothelium. Meanwhile, phacoemulsification has a great effect on morphology of corneal endothelium in diabetic group, and recovery of morphology of corneal endothelium is slower. Diabetes may be associated with the occurrence of intraoperative floppy iris syndrome.