Reading glasses are spherical plus lenses used for the compensation of presbyopia. They are often available without a prescription even if one is normally required for other types of glasses. Cheap drug store reading glasses are not customized to your PD measurement, and may be of inferior lens quality. Plus lens therapy has mixed results and should be used with caution in the prevention of myopia in children and in tackling the last diopter in the EM method. Reading glasses may be useful as differentials to tone down the power of contacts, but should be customized to your PD and your distance to blur, so it may be best to order them custom just like any other lens.