To investigate the effect of phacoemulsification using different corneal micro-incision sizes on the postoperative corneal healing.

A non-random controlled study was performed.Seventy-six patients (76 eyes) with age-related cataract who underwent phacoemulsification and cataract extraction combined with intraocular lens (IOL) implantation in Yanbian University Hospital from May 2016 to May 2017 were enrolled.The subjects were divided into 2.2 mm incision group (37 eyes) and 1.8 mm incision group (39 eyes) according to corneal incision size.The intraoperative cumulative dissipated energy (CDE) and ultrasound time of the two groups were measured and compared.The corneal incision structure and corneal thickness of operative eyes were measured by anterior segment optical coherence tomography before surgery and at postoperative 1 day, 1 week and 1 month.The corneal endothelial cells count, the central corneal thickness (CCT), and the corneal volume in the central corneal diameters of 3.0 mm (CV3) and 10.0 mm (CV10) were measured by Pentacam.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Yanbian University Hospital (No.2015153), and written informed consent was obtained from all subjects before surgery.

There were statistically significant differences in the corneal endothelial cells count, CCT, CV3, CV10, and corneal thickness at epithelial side of the incision between pre-operation and post-operation in each group (F_time=17.717, 67.356, 17.577, 13.559, 80.076; all at P<0.01).But there was no statistically significant difference in the indexes between the two groups (F_group=0.788, 0.706, 3.692, 4.341, 4.182; all at P>0.05).The number of corneal endothelial cells in the two groups was gradually decreased after surgery, and was significantly reduced at one month after surgery in comparison with the pre-operation, and the differences were statistically significant (both at P<0.05).At 1 day after surgery, the CCT, CV3, CV10, and corneal thickness at epithelial side of the incision in the two groups were increased significantly in comparison with the pre-operation and the differences were statistically significant (all at P<0.05), and the differences were not statistically significant between preoperative and postoperative 1 week or 1 month (all at P>0.05).With time going by, the indexes were back to normal gradually.The incidence of endothelial gaping and dislocation at the corneal incision in the 1.8 mm incision group was 12.8% (5/39) and 5.1% (2/39), which were significantly higher than 0.0% (0/37) and 2.7% (1/37) in the 2.2 mm incision group, and the differences were statistically significant (χ²=5.078, P=0.024; χ²=0.295, P=0.590).At 1 day after surgery, corneal thickness at the endothelial side in the 1.8 mm incision group was significantly thicker than that in the 2.2 mm incision group, and the difference was statistically significant (P=0.042), and the corneal thickness at endothelial side of the incision was positively correlated with CDE in the two groups (r=0.231, P=0.025; r=0.347, P=0.003).

Compared with 2.2 mm incision, 1.8 mm corneal incision results in higher incidence of endothelial gaping and dislocation at the corneal incision, greater corneal thickness at endothelial side of the incision and slower recovery.

Cataract; Phacoemulsification; Corneal incision; Anterior segment optical coherence tomography; Pentacam