There are FDA regulations governing which particular excimer laser may be used to correct which particular type and degree of refractive error. For instance, our VISX laser here at the Beeve Vision Care Center is approved for LASIK treatment of nearsightedness up to -14.0 diopters with or without up to -5.0 diopters of astigmatism, It is also approved for correction of farsightedness, up to +5.0 diopters with or without up to +4.0 diopters of astigmatism. These are high amounts of refractive error and include most nearsighted people.