Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part II - Choosing the correct haptic fixation and intraocular lens design to help eradicate posterior capsule opacification

Purpose: Posterior capsule opacification (PCO) is one of the most common co mplications of cataract surgery, and there is an urgent need to reduce its incidence. Its main treatment, neodymium:YAG (Nd,YAG) laser posterior capsu lotomy, may be associated with significant morbidity and is expensive. In t his study, the authors ascertain the effect of posterior chamber intraocula r lens (PC-IOL) fixation and various IOL designs (rigid polymethyl methacry late [PMMA] optic and small-incision foldable designs) on the pathogenesis of PCO, Design: Prospective analysis of pseudophakic eyes obtained postmortem. Participants: A total of 3493 eyes with PC-IOLs obtained postmortem and rec eived between 1984 and 1998, Methods: Miyake-Apple posterior photographic technique. Main Outcome Measures: Peripheral Soemmering's ring, central PCO in the vis ual axis, and eyes that have had Nd,YAG laser posterior capsulotomy were an alyzed and scored, and these findings were correlated with the type of fixa tion and IOL design. Results: The degree of formation of peripheral Soemmering's ring was not in fluenced by IOL fixation, The acrylic design revealed relatively low Soemme ring's ring scores. In contrast, central PCO and Nd:YAG laser capsulotomy s cores were consistently influenced by fixation, The scores were significant ly lower in eyes with in-the-bag fixation, The bag-bag fixated acrylic-PMMA design and the three modern silicone IOL designs analyzed in this study ha d less central PCO and lower posterior capsulotomy scores than did the PMMA IOLs, Conclusions: The formation of peripheral PCO (the Soemmering's ring), the p recursor of clinically significant, vision-threatening PCO, is not signific antly influenced by the haptic fixation pattern. It is much more dependent on the quality and thoroughness of surgical cortical cleanup. Reduction of Soemmering's ring is an important goal because the retained regenerative co rtical cells within this lesion are the cells of origin of PCO, The acrylic IOL design was associated with a lessor amount of peripheral Soemmering's ring as compared with all other designs. In sharp contrast to peripheral PCO, fixation of the IOL was a highly signi ficant factor affecting the formation and quantity of central PCO-the clini cally significant opacity behind the IOL optic, measured in this series eit her by scoring an intact retro-optical membrane or by documenting the prese nce of a Nd:YAG laser posterior capsulotomy orifice. The quantity of centra l PCO was consistently much lower in eyes with in-the-bag fixated IOLs comp ared with lenses with one or both haptics out of the bag. This is best expl ained by the fact that secure in-the-bag fixation positions the IOL optic i n the best possible position to create a barrier effect. The lowest PCO rat es were generally noted with the acrylic and modern silicone IOL designs.