More than half of vision impairment is caused by refractive error. Long sighted or short sighted vision, astigmatism and presbyopia (loss of vision due to age) can be detected by routine eye examination. These types of refractive error are a major cause of vision loss. Refractive errors are commonly treated using corrective lenses, such as spectacles or contact lenses. Refractive surgery can also be used to correct some refractive disorders.