The proportion of students with visual impairment due to refractive error in recent years has been increased in Vietnam, from an estimated 2.5% in 2002 to 10%-25% in 2007 (RAAB statistics). The problem was found to be much more common in students in urban than in rural settings (26.1% vs. 14.4%). According to a recent study conducted by the Institute of Educational Science in 2008, the rate of refractive errors in students increased dramatically as students progressed through school stages with rates of 18.7% in primary, 23.5% in lower secondary and 32.7% in upper secondary school.