Errors of refraction of the eye can be corrected not only by means of spectacles, contact lenses or intra-ocular lenses, but also by operative procedures on the cornea. At present, correction of myopia is accomplished with radial keratotomy (RK), a procedure that achieves the best results in the range up to - 6.0 diopters. However, on account of its side effects, in particular poor predictability, the method is no true alternative to the use of optical aids. Epikeratoplasty done to correct hyperopia and aphakia, is even more imprecise, and should only be employed in exceptional cases. Laser surgery of the cornea is still undergoing clinical testing, but has already produced promising results.