Laser refractive surgery.

BACKGROUND: Refractive errors; myopia, hypermetropia and astigmatism, have traditionally been corrected by glasses and more recently contact lenses. For nearly 100 years surgical techniques to treat such disorders have also been developed. The latest of these are based upon the use of the excimer laser to ablate the corneal stroma either directly under the corneal epithelium (surface PRK) or under a flap of superficial stroma (LASIK). OBJECTIVE: To look at the development of laser refractive surgery and to put this in the context of appropriate and inappropriate indications for usage. DISCUSSION: While the development of such techniques has revolutionised the field of refractive surgery unrealistic expectations with regard to the outcome of such procedures may have been raised in recent advertising by some ophthalmologists and laser centres. The most important influence on the refractive outcome of such procedures is the pre-operative refraction. The best outcomes are seen with treating low degrees of myopia and/or astigmatism. Outcomes for treating high degrees of myopia or astigmatism are often disappointing. The treatment of hypermetropia remains experimental.