Refractive error means that the shape of your eye does not bend light correctly, resulting in a blurred image.
Worldwide, it is a relatively common cause of vision being significantly reduced. Untreated refractive error can result in a person’s vision being so poor that they are classified as being blind.
Four Types of Refractive Errors
Myopia: (nearsightedness) is a condition where objects up close appear clearly, while objects far away appear blurry. With myopia, light comes to focus in front of the retina instead of on the retina.
Hyperopia: (farsightedness) A condition where distant objects may be seen more clearly than objects that are near. However, people experience hyperopia differently. For people with significant hyperopia, vision can be blurry for objects at any distance.
Astigmatism: Astigmatism occurs when the front surface of your eye (cornea) or the lens, inside your eye, has a slightly different surface curvature in one direction from the other. Instead of being smooth in all directions, the surface may have some areas that are flatter or steeper. Astigmatism blurs your vision at all distances. Astigmatism can also occur in combination with myopia and hyperopia.
Presbyopia: It is an age-related condition in which the ability to focus up close becomes more difficult. As the eye ages, the lens can no longer change shape enough to allow the eye to focus close objects clearly. This normal aging process of the lens can also be combined with myopia, hyperopia or astigmatism.
A refractive error can be diagnosed by an eye care professional during a routine eye examination. Testing usually consists of asking the patient to read a vision chart while testing an assortment of lenses to maximize a patient’s vision.
Refractive errors are commonly treated using corrective lenses, such as eyeglasses or contact lenses. Refractive surgery (LASIK) can also be used to correct some refractive disorders. Presbyopia, by itself can sometimes be treated with over-the-counter reading glasses.