O.138, Yixueyuan Road, Xuhui, Shanghia 200032, China. Received: 3 July 2012 Accepted: 25 March 2013 Published

Saw SM, Husain R, Gazzard GM, Koh D, Widjaja D, Tan DT: Causes of low vision and blindness in rural Indonesia. Br J Ophthalmol 2003, 87:1075?078. five. Resnikoff S, Pascolini D, Mariotti SP, Pokharel GP: Global magnitude of visual impairment brought on by uncorrected refractive errors in 2004. Bull Planet Health Organ 2008, 86:63?0. six. Foster A, Resnikoff S: The influence of Vision 2020 on global blindness. Eye 2005, 19:1133?135. 7. Xu L, Wang Y, Li Y, Wang Y, Cui T, Li J, Jonas JB: Causes of blindness and visual impairment in urban and rural places in Beijing: the Beijing Eye Study. IKK 16 web Ophthalmology 2006, 113:1134. eight. Kuang TM, Tsai SY, Hsu WM, Cheng CY, Liu JH, Chou P: Correctable visual impairment in an elderly Chinese population in Taiwan: the HC-030031 Shihpai Eye Study. Invest Ophthalmol Vis Sci 2007, 48:1032?037. 9. Zhao J, Ellwein LB, Cui H, Ge J, Guan H, Lv J, Ma X, Yin J, Yin ZQ, Yuan Y, Liu H: Prevalence of vision impairment in older adults in rural China: the China Nine-Province Survey. Ophthalmology 2010, 117:409?16. 10. Fotouhi A, Hashemi H, Raissi B, Mohammad K: Uncorrected refractive errors and spectacle utilisation price in Tehran: the unmet need. Br J Ophthalmol 2006, 90:534?37. 11. Dandona R, Dandona L: Refractive error blindness. Bull Planet Overall health Organ 2001, 79:237?43. 12. Holden BA, Resnikoff S: The function of optometry in Vision 2020. Neighborhood Eye Health 2002, 15:33?six. 13. Abdull MM, Sivasubramaniam S, Murthy GV, Gilbert C, Abubakar T, Ezelum C, Rabiu MM, Nigeria National Blindness and Visual Impairment Study Group: Causes of blindness and visual impairment in Nigeria: the Nigeria national blindness and visual impairment survey. Invest Ophthalmol Vis Sci 2009, 50:4114?120. 14. Zhao J, Ellwein LB, Cui H, Ge J, Guan H, Lv J, Ma X, Yin J, Yin ZQ, Yuan Y, Liu H: Prevalence of vision impairment in older adults in rural China: the China Nine-Province Survey. Ophthalmology 2010, 117:409?16. 10. Fotouhi A, Hashemi H, Raissi B, Mohammad K: Uncorrected refractive errors and spectacle utilisation price in Tehran: the unmet need. Br J Ophthalmol 2006, 90:534?37. 11. Dandona R, Dandona L: Refractive error blindness. Bull Globe Overall health Organ 2001, 79:237?43. 12. Holden BA, Resnikoff S: The function of optometry in Vision 2020. Neighborhood Eye Health 2002, 15:33?6. 13. Abdull MM, Sivasubramaniam S, Murthy GV, Gilbert C, Abubakar T, Ezelum C, Rabiu MM, Nigeria National Blindness and Visual Impairment Study Group: Causes of blindness and visual impairment in Nigeria: the Nigeria national blindness and visual impairment survey. Invest Ophthalmol Vis Sci 2009, 50:4114?120. 14. Gerontological Society of Shanghai.2009 Shanghai Monitored Statistical Details on Population of the Elderly Development of Old age Program. http://www.shanghaigss.org.cn/news_view.asp?newsid=6895. 15. Baoshan Statistical Yearbook. 2009. http://bstz.baoshan.sh.cn:8080/pub/bstj/ tjsj/tjnj/201007/t20100719_33511.html. 16. Shanghai Baoshan People'Government. http://zfxxgk.baoshan.sh.cn:8989/pub/ bsqzf/zfxxgk_1/tjsj/tjgb/201108/t20110802_3679.html.17. Zhao J, Jia L, Sui R, Ellwein LB: Prevalence of blindness and cataract surgery in Shunyi County. China. Am J Ophthalmol. 1998, 126:506?14. 18. Li S, Xu J, He M, Wu K, Munoz SR, Ellwein LB: A survey of blindness and cataract surgery in Doumen County. China. Ophthalmology.