To investigate the clinical effect and safety of two-step capsulorhexis in phacoemulsification with intraocular lens (IOL) implantation for hypermature cataract.

A non-randomized controlled clinical trial was carried out in Huaibei People's Hospital.Forty eyes of 40 patients with hypermature cataracts were enrolled from January 2016 to March 2017.The patients were divided into 2 groups according to different capsulorhexis.Two-step curvilineal capsulorhexis was used during the phacoemulsification with IOL implantation in 20 eyes of the 20 patients in the two-step capsulorhexis group (to complete a 4 mm-diameter capsulorhexis with the ripping forceps firstly and then extented the capsulorhexis diameter until 5-6 mm), and conventional curvilineal capsulorhexis was used during the phacoemulsification with IOL implantation in 20 eyes of the 20 patients in the conventional capsulorhexis group.The demography was matched between the two groups and the same foldable IOLs were used in the surgery.The uncorrected visual acuity, successful rate of capsulorhexis, intra- and post-operative complications were compared.

The postoperative visual acuity was considerably improved both in the two groups after surgery.The UCVA in postoperative 1 day and 3 days were 4.70±0.09 and 4.70±0.08 in the two-step capsulorhexis group, which were significantly better than 4.60±0.08 and 4.60±0.08 in the conventional capsulorhexis group (both at P<0.05), and no significant differences were found in the UCVA in postoperative 7 days, 1 month and 3 months between the two groups (all at P>0.05). The successful rate of capsulorhexis in the two-step capsulorhexis group was 100% (20/20), which was significantly higher than 80% (16/20) in the control group (χ²=4.44, P<0.05). Posterior capsule rupture occurred in 4 eyes in the conventional capsulorhexis group, and no posterior capsule rupture was found in the two-step capsulorhexis group (χ²=4.44, P<0.05). The incidence rates of corneal edema in postoperative 1 day and 3 days were 40% and 45% in the conventional capsulorhexis group, which were significantly higher than 10% and 15% in the two-step capsulorhexis group (χ²=4.80, 4.19, both at P<0.05), and the corneas were clear in 7 days after surgery.No significant differences were found in intraocular pressure between groups and various time points (F_group=0.091, P=0.765; F_time=7.048, P>0.05).

Two-step capsulorhexis during phacoemulsification with IOL implantation for hypermature cataract is safe and effective in improving the successful rate of continuous curvilineal capsulorrhexis, reducing intra-operative and postoperative complications, and it is beneficial to the recovery of postoperative visual acuity.

Cataract/surgery; Phacoemulsification; Treatment outcomes; Safety; Continuous curvilineal capsulorrhexis; Hypermature cataract