Near-sightedness, also known as short-sightedness and myopia, is a condition of the eye where light focuses in front of, instead of on, the retina. This causes distant objects to be blurry while close objects appear normal. The underlying cause is believed to be a combination of genetic and environmental factors. Farsightedness, also known as hyperopia, is a common type of refractive error where distant objects may be seen more clearly than objects that are near.