Not everyone who wears glasses is a person with a disability under the ADA. Although the ADA generally requires that the positive effects of mitigating measures be ignored in assessing whether someone has a disability, the law requires that one consider the positive effects of the use of ordinary eyeglasses or contact lenses (that is, lenses that are intended to fully correct visual acuity or to eliminate refractive error). If the use of ordinary lenses results in no substantial limitation to a major life activity, then the person's vision impairment does not constitute a disability under the first part of the ADA's definition of disability.