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Implanted Lenses May Treat Milder Nearsightedness

Study: Phakic Intraocular Lenses Are as Safe and Effective as Standard Laser Eye Surgery
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By Katrina Woznicki
WebMD Health News
Reviewed by Laura J. Martin, MD

May 12, 2010 -- An eye operation typically reserved for patients with severe nearsightedness may be a safer alternative to standard laser eye surgery for patients with less severe forms of nearsightedness, according to a new report published in the recent issue of The Cochrane Library.

Researchers at Moorfields Eye Hospital NHS Foundation Trust in London reviewed three clinical trials that randomly assigned patients to different types of surgery used to correct nearsightedness (myopia). 

Myopia is the leading cause of vision impairment around the globe, according to the World Health Organization.In the U.S., 32 million people aged 40 and older are myopic.

The more common surgical procedure, excimer laser refractive surgery, treats myopia by removing parts of the cornea. The second procedure, which is relatively new and not used as widely, implants a thin lens called a phakic intraocular lens (IOL) permanently into the eye to eliminate the need for eyeglasses or contact lenses. Both procedures change the path of light entering the eye and bring images into sharper focus. Phakic IOLs were approved by the FDA in 2004.

Phakic IOLs: Risk of Cataracts

The study showed that one year after undergoing the procedure, 20/20 vision without eyeglasses was the same for patients who received either laser surgery or phakic IOLs.  One year after the surgical procedure, the phakic IOL patients had clearer spectacle-corrected vision, better contrast sensitivity (the ability to perceive differences between an object and its background), and higher satisfaction scores than laser eye surgery patients. However, there was a slight increased risk of developing cataracts among the phakic IOL group.

The researchers' conclusions were based on three clinical trials that included a total of 228 eyes in 132 men and women ranging in age from 21 to 60. The patients had moderate to severe myopia.

The advantages of phakic IOLs are that "it does not involve removing any corneal tissue, and it is reversible. ... In the unlikely event of any problems the synthetic lens can be removed at a later date,” study author Allon Barsam tells WebMD in an email interview.

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