[1] Sun Yat Sen Univ, Sch Publ Hlth, Guangzhou 510080, Peoples R China
[2] Guangzhou Med Univ, Sch Publ Hlth, Guangzhou, Peoples R China
[3] Southern Med Univ, Affiliated Hosp 7, Ctr Gen Practice, Foshan, Peoples R China
[4] Digital Educ Holdings Ltd, EDU, Fac Med & Hlth, Kalkara, Malta
[5] Univ Oxford, Green Templeton Coll, Oxford, England
[6] Sun Yat Sen Univ, Zhongshan Ophthalm Ctr, State Key Lab Ophthalmol, Guangzhou, Peoples R China
[7] Sun Yat Sen Univ, Zhongshan Ophthalm Ctr, Guangdong Prov Key Lab Ophthalmol & Visual Sci, Guangzhou, Peoples R China
[8] Hebei Med Univ, Dept Gen Practice, Hosp 2, Shijiazhuang, Peoples R China
[9] Chinese Univ Hong Kong, Fac Med, JC Sch Publ Hlth & Primary Care, Hong Kong, Peoples R China