Article History
Received: 23 March 2020
Accepted: 25 May 2020
First Online: 17 June 2020
Ethics approval and consent to participate
: This study was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the Ethics Committee of the Tianjin Eye hospital. Written informed consent was obtained from all participants.
: Not applicable.
: The Authors declare that there is no conflict of interest.