What is refractive error?
Refractive error occurs when the cornea and lens do not clearly focus light onto the retina at the back of the eye. This means that vision can be blurry. The most common types of refractive errors are myopia (short-sightedness), hyperopia (long-sightedness) and astigmatism. Presbyopia, which occurs because the lens inside the eye gradually loses the flexibility required to change focus, is a common cause of blurred vision in people over 40 years of age. For most cases of refractive error, wearing glasses or contact lenses can restore clear vision. Laser surgery can correct some types of refractive error.