1. Department of Ophthalmology, Lanzhou University Second Hospital, Lanzhou, Gansu, China
2. Department of Ophthalmology, Gansu Provincial Hospital, Lanzhou, Gansu, China
3. Evidence Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
4. Department of Ophthalmology, The Chinese People’s Liberation Army General Hospital, Beijing, China