8Xu L,Wang Y,Li Y,et al.Causes of blindness and visual impairment in urban and rural areas in Beijing: the Beijing Eye Study.Ophthalmology,2006,113 (7) :1134
9Saw SM, Husain RM, Gazzard GM,et al.Causes of low vision and blindness in rural Indonesia.Br J Ophthalmol,2003,87(9):1075
10Iwase A,Araie M,Tomidokoro A,et al.Prevalence and causes of low vision and blindness in a Japanese adult population:the Tajimi Study. Ophthalmology,2006,113(8): 1354
