Laser surgery to correct vision problems has been in use since the early 1990s. Photorefractive Keratotomy (PRK) is typically used to correct low to moderate myopia, while laser in-situ keratomileusis (LASIK) is preferred for high myopia corrections.
Although over 18 million LASIK procedures have been performed worldwide, there is still some controversy regarding the maximum correction possible and efficacy with this technique.
In an article published in the January 2008 issue of the American Journal of Ophthalmology, researchers from Miguel Hernandez University, Medical School, Alicante, Spain; and Ankara University School of Medicine, Ankara, Turkey; report on a study of high myopia patients ten years after LASIK surgery. The findings show that LASIK for myopia over -10 D is a safe and effective procedure in the long-term.
196 high myopic eyes of 118 patients, preoperatively needing at least 10 diopter (10 D) corrections to achieve 20/20 vision, were evaluated ten years following surgery. Uncorrected vision was 77% of best-corrected vision (BSCVA) before surgery.
BSCVA improved 1 line. Only 5% of eyes lost more than 2 lines of BSCVA and 40% avoided the use of glasses. 119 (61 %) of eyes were within ± 2.00 Diopters at 10 years. Only 2 eyes (1%) developed corneal ectasia. The retreatment rate was 27%.
According to lead investigator Jorge L. Alió, 'These results are extremely encouraging considering that this refractive correction implies the maximum limit of application of this technique. This study has allowed us to demonstrate that, in spite of the prejudices about the limits of LASIK technique, the results regarding predictability, efficacy and safety for high myopic patients are very good in the long term.
The optimum limit of predictability for this technique is around 10 D of myopia. This reference study, with a long time perspective, allows us to know the safety, precision and limits of LASIK in highly myopic eyes.'