1. Department of Ophthalmology, Tongzhou Maternal and Child Health Hospital of Beijing, Beijing, China
2. Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
3. Anyang Eye Hospital, Henan Province, Anyang, China
4. Department of Ophthalmology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
5. Department of Epidemiology and Health Statistics, Peking University School of Public Health, Beijing, China