Myopia is a refractive defect in which the image of distant objects is formed in front of the retina, rather than on the retina itself, making vision indistinct, while vision of objects at a short distance remains clear and distinct.
It is the most common of the refractive eye defects, and its prevalence has increased in recent decades: a study by the National Eye Institute (NEI), estimated that myopia has increased in the U.S. population aged 12 to 54 years from a prevalence of 25 percent in 1971-1972 to 41.6 percent in 1999-2004.
