Myopia, or near-sightedness, is a condition where distant objects appear blurry, whereas near objects appear clear. It is the most common refractive error and in the United States, affects approximately 40% of individuals. In China, it affects 90% of all children. It is caused, in general, by an anatomically long eye. Clear images are focused by the cornea and lens to the back of the eye, called the retina. In a patient who is myopic, the image is focused (blurred) in front of the retina. It is treated with glasses or contact lenses in children. Adults can potentially have the option of having LASIK or PRK to treat their myopia.