NICE guidance on laser correction of refractive error following non-refractive ophthalmic surgery
Refractive errors include common conditions such as myopia (short-sightedness) and hyperopia (long-sightedness) which impede the accuracy of vision without spectacles or contact lenses. Laser surgery aims to establish visual accuracy by changing the shape of the cornea (the clear outer layer at the front of the eye), so that light rays are more precisely directed onto the retina. Three types of laser correction are considered in this guidance: photorefractive keratectomy (PRK), laser epithelial keratomileusis (LASEK) and laser in situ keratomileusis (LASIK).