Within the past two decades, surgical methods have been developed to permanently correct myopia (short- or nearsightedness). The two most common procedures are photorefractive keratectomy (PRK) and lasik. In a review that compares these two vision-correction surgeries, Dr. Alex J. Shortt of the Institute of Ophthalmology and Dr. Bruce D.S. Allan of Moorfields Eye Hospital, both in London, found that, although PRK was approved by the FDA first, lasik has become more popular. Both procedures use a laser to correct myopia by altering the cornea, but PRK does this by removing small layers of the tissue, while lasik opens a flap of the cornea and removes excess tissue underneath. The authors looked at six trials that yielded information on surgeries in a total of 417 eyes, 201 of which received PRK and 216, lasik. Their analysis revealed that less pain is experienced during PRK than with lasik, that recovery from lasik is faster and less painful than recovery from PRK, and that postsurgery vision acuity and accuracy are comparable for both procedures. Both surgeries showed some minor negative effects, however. PRK resulted in a slight loss in best spectacle-corrected visual acuity as well as occasional visual side effects such as haze and glare. Lasik surgery occasionally had complications related to the corneal flap, though these problems had mostly mild or negligible permanent effects. The authors also noted that lasik may be safer than PRK but that not enough data was available to make a definitive conclusion. (The Cochrane Database of Systematic Reviews, April 2006, Issue 2: CD005135.)