Received: 6 August 2019
Accepted: 3 April 2021
First Online: 1 May 2021
: This study adhered to the tenets of the Declaration of Helsinki. This study was approved by the Peking Union Medical College Hospital Review Board. The committee’s reference number is ZS-1976. All participants provided their written informed consent to participate in the study.
: Not applicable.
: One of the authors, Youxin Chen, is a member of the editorial board of BMC ophthalmology. No other competing interests exist.