1 Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing 100730, China.
2 Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing 100730, China. Email: mmzxy@yahoo.com.
3 Department of Epidemiology & Biostatistics, School of Basic Medicine, Peking Union Medical College & Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing 100005, China.