Uncorrected refractive error remains a major cause of vision loss throughout the world. When included in the global statistics, uncorrected refractive error accounts for over 18% of profound vision loss, with a much larger percentage of moderate and severe vision loss. Ref: Pirbhai A, Kent S, Hodge W.G. (2011). Chapter 20. Causes and Prevention of Vision Loss. In Riordan-Eva P, Cunningham E.T., Jr (Eds), Vaughan & Asbury's General Ophthalmology, 18e.