Nearsighted? New Procedure Better than Laser
For people who are nearsighted (myopic), correction can come in the form of eyeglasses, contact lenses, excimer laser refractive surgery, or a new procedure, insertion of phakic intraocular lenses (IOLs). A recent study shows that while laser and IOLs produced similar results, patients liked the newer procedure better than laser.
Nearly one-third of the US population is nearsighted, according to the American Optometric Association, a condition in which close objects are seen clearly but objects farther away appear blurred. Myopia typically first occurs in school-age children and progresses until about age 20. However, it can also develop during adulthood due to health conditions such as diabetes or visual stress.
The latest Cochrane Database Systematic Review notes that individuals prefer phakic intraocular lens implantation over excimer laser refractive surgery to correct nearsightedness. The laser approach has been popular among people who do not want to wear eyeglasses or contact lenses. Until this latest review, however, researchers had no systematic review that compared the accuracy and safety of the laser technique with the newer IOLs.
Excimer laser refractive surgery alters the path of light that enters the eye and brings images into focus in the right place in the eye. This is accomplished by removing portions of the cornea. Insertion of phakic intraocular lenses accomplishes the same goal, but does so by placing a synthetic lens in front of the eye’s natural lens.
The investigators reviewed data from three trials in which laser and IOL procedures were performed. A total of 228 eyes in 132 patients were treated. One year after surgery, the percentage of eyes with 20/20 vision without eyeglasses was the same regardless of the procedure, but patients who had an IOL implant had clearer vision when using eyeglasses and better contrast sensitivity. Patients who had undergone the IOL procedure also scored higher in patient satisfaction.
Until now, IOL implantations have been done in more severely nearsighted patients, but results of this latest review suggest IOLs could be used in a wider range of nearsighted patients. Allon Barsam of the Moorfields Eye Hospital NHS Foundation Trust in London, the study’s lead author, noted that the phakic IOL procedure has a slightly increased risk of cataract development, and that further research of long-term side effects is necessary.
The Food and Drug Administration (FDA) has approved two phakic IOLs: an iris-fixated and a posterior-chamber IOL. According to a recent study published in Ophthalmology, FDA trials of iris-fixated IOLs resulted in uncorrected visual acuity of 20/40 or greater in 84 percent and 20/20 or better in 31 percent after three years. In posterior-chamber IOLs, 20/40 or greater was achieved in 81 percent and 20/20 or greater was reached in 41 percent.
Barsam noted that “it could be worth considering phakic IOL treatment over the more common laser surgery” for individuals who are moderately nearsighted. For the millions of people who are nearsighted, phakic IOL is an option to laser surgery to be discussed with their ophthalmologist.
American Optometric Association
Barsam A, Allan BDS. Cochrane Database of Systemic Reviews 2010; issue 5, art. CD007679
Huang D et al. Ophthalmology 2009 Nov; 116(11): 2244-58