Refractive surgery includes all procedures which are primarily targeted at 
changing the refractive power of the eye. Currently laser-assisted in situ 
keratomileusis (LASIK) is indicated to correct myopia of up to - 8 D, hyperopia 
up to + 3 D and astigmatism up to 5 D. Photorefractive keratectomy (PRK) and 
laser epithelial keratomileusis (LASEK) are primarily recommended for myopia up 
to - 6 D and for greater refractive errors, phakic intraocular lenses (IOL) are 
the first choice (myopia greater than - 6 D and hyperopia greater than + 3 D). 
If presbyopia is present in addition to the high refractive error, refractive 
lens exchange is another alternative.