Phakic Intraocular Lenses May Prove Safer Than Excimer Laser for Moderate to High Myopia

Emma Hitt, PhD

May 13, 2010

May 13, 2010 — Phakic intraocular lenses (IOLs) may be safer than excimer laser surgical correction for moderate to high myopia and appear to be preferred by patients, according to a new study published online May 12 in the Cochrane Database of Systematic Reviews.

Allon Barsam, BDS, from the Moorfields Eye Hospital National Health Service Foundation Trust, London, United Kingdom, and colleagues point out that excimer laser refractive surgery removes corneal stroma to lessen the refractive power of the cornea, whereas phakic IOLs diverge light rays. Both methods bring the image of a viewed object into focus on the retina, rather than in front of it.

The authors sought to compare the effect of excimer laser refractive surgery with that of phakic IOLs in patients with myopia, defined as greater than 6.0 to −20 diopters with up to 4.0 diopters of myopic astigmatism. They searched several databases, finding 3 randomized controlled trials (RCTs) including 228 eyes that met eligibility criteria, and analyzed the data collectively per standard Cochrane methods.

The percentage of eyes with uncorrected visual acuity of 20/20 or better at 12 months after treatment was comparable. Phakic IOL surgery resulted in significantly less loss of best spectacle-corrected visual acuity at 12 months postoperatively compared with excimer laser surgical correction, although neither technique caused a loss of final best-spectacle corrected visual acuity.

Early cataract development, although rare, was more common with phakic IOLs. However, contrast sensitivity and patient preference scores were higher with phakic IOL surgery than with excimer laser correction.

Limitations of this review include that the 3 RCTs used in the meta-analysis were small in number and of short duration. Given these factors, some serious adverse events could have been missed in these trials.

"While phakic IOLs might be accepted clinical practice for higher levels of myopia...it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 [diopters] of myopic spherical equivalent with or without astigmatism)," the authors conclude. "[Additional] RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs."

The authors have disclosed no relevant financial relationships.

Cochrane Database Syst Rev. Published online May 12, 2010.

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