Safer Alternative to Refractive Laser Eye Surgery?

Insertion of phakic intraocular lenses (IOLs), a new procedure for correcting shortsightedness, could be safer than excimer laser refractive surgery, according to a new study.

Researchers at Moorfields Eye Hospital NHS Foundation Trust (London, United Kingdom) conducted a systematic review of studies comparing the accuracy and safety of excimer laser refractive surgery and insertion of phakic IOLs. The researchers reviewed data from randomized controlled trials (RCTs) comparing the two procedures for the correction of myopia greater than 6 diopters (D) spherical equivalent. In all, three trials were found comparing the two types of surgery, which together included surgeries performed on 228 eyes in 132 patients. The range of myopia of included patients was -6 D to -20 D of myopia with up to 4 D of myopic astigmatism.

The researchers found that the percentage of eyes with 20/20 vision (without spectacles) was the same for both procedures, but patients undergoing phakic IOL treatment had clearer spectacle corrected vision. Phakic IOL surgery was found to be safer than excimer laser surgical correction for moderate to high myopia, as it resulted in significantly less loss of best spectacle corrected visual acuity (BSCVA) at 12 months postoperatively; however, there was a low risk of developing early cataract with phakic IOLs. Phakic IOL surgery also appeared to result in better contrast sensitivity than excimer laser correction for moderate to high myopia, as well as scoring more highly on patient satisfaction and preference questionnaires. The study was published in the May 12, 2010, issue of Cochrane Systematic Review.

"Our findings suggest phakic IOLs are safer than excimer laser surgery for correcting moderate to high levels of short-sightedness,” said coauthor Allon Barsam, M.D. "Although it's not currently standard clinical practice, it could be worth considering phakic IOL treatment over the more common laser surgery for patients with moderate short-sightedness.”

Myopia is a condition in which the focusing power (refraction) of the eye is greater than that required for clear distance vision. There are two main types of surgical correction for moderate to high myopia; the more traditional excimer laser refractive surgery works by removing corneal stroma to lessen the refractive power of the cornea, and to bring the image of a viewed object into focus onto the retina, rather than in front of it. Phakic IOLs, on the other hand, work by diverging light rays so that the image of a viewed object is brought into focus onto the retina, rather than in front of it. They can be placed either in the anterior chamber of the eye in front of the iris, or in the posterior chamber of the eye between the iris and the natural lens.

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Moorfields Eye Hospital NHS Foundation Trust