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Optic design plays greater role in reducing PCO than IOL material
Silicone and hydrophobic acrylic IOLs with a sharp edge design had a similar effect in inhibiting PCO.
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A rectangular, sharp optic IOL edge has a greater effect in preventing posterior capsular opacification than the IOL material, according to a recent clinical study. Silicone and hydrophobic acrylic IOLs seemed to be equally effective in preventing the development of PCO, the study found.
“At this point, I believe that the choice between these two materials is a matter of taste,” said Oliver Findl, MD, in an e-mail interview with Ocular Surgery News. “Longer-term results of randomized clinical trials may provide more information.”
Dr. Findl and colleagues compared the formation of PCO on two types of IOL in a randomized controlled trial with a 3 year follow-up. The two IOL models were the hydrophobic acrylic Alcon AcrySof and silicone Advanced Medical Optics CeeOn Edge 911A.
Both are three-piece IOLs. The study authors said that, because the two lenses were “very comparable” in their design, “differences found in this study should be interpreted primarily as an optic material effect.”
“For hydrophobic materials, edge design seems to play a more important role in PCO inhibition than optic material,” the authors said. Further research will be necessary to determine if the same is true for hydrophilic acrylic materials.
No difference
Dr. Findl and colleagues randomized 56 eyes of 28 patients with cataracts to receive the silicone IOL in one eye and the hydrophobic acrylic IOL in the fellow eye. Both IOL designs feature sharp, truncated posterior optic edges. Patients were evaluated at 1 and 3 years after surgery.
At both follow-up time points, the amount of PCO as measured by automated image analysis did not differ between the silicone and acrylic IOLs. The researchers also did not observe any differences in best-corrected visual acuity, rhexis/IOL overlap, capsular folds or the amount of anterior capsular opacification (ACO) during the follow-up period.
Other than the optic material, the chief differences between the two IOLs were optic convexity and haptic design, they said. The haptic of the AcrySof is a J-loop, while the AMO IOL has a C-loop design. The silicone IOL has a symmetrical biconvex optic and the acrylic IOL has an asymmetrical optic with a flatter anterior surface than posterior surface.
“Theoretically, these slight differences in haptics geometry may influence PCO performance,” the authors said.
For Your Information:
- Oliver Findl, MD, can be reached at University of Vienna AKH-Wien, Dept. of Ophthalmology, Währinger Gürtel 18-20, 1090, Vienna, Austria; +43-1-40400-7967; fax: +43-1-40400-7881; e-mail: oliver.findl@meduniwien.ac.at.
- Advanced Medical Optics, manufacturer of the CeeOn Edge silicone 911A IOL, the PhacoFlex SI40 IOL and the Clariflex IOL, can be reached at 1700 E. St. Andrew Place, P.O. Box 25162, Santa Ana, CA 92799-5162 U.S.A.; +1-714-247-8200; Web site: www.amo-inc.com.
- Alcon Laboratories, manufacturer of the AcrySof foldable IOL, can be reached at 6201 S. Freeway, Fort Worth, TX 76134-2099 U.S.A.; Web site: www.alconlabs.com.
- Kim Norton is an OSN Correspondent based in Mount Laurel, U.S.A.