Postoperative measurements of BCVA and M-score were conducted at 2- and 6-month follow-up visits by independent masked observers. The first postoperative SD-OCT scanning was usually conducted at 1 to 2 weeks after operation according to the intraocular gas status. Then, OCT scans were conducted at follow-up visits 2, and 6 months postoperatively. The same experienced examiner conducted all the OCT scans on all subjects.