title: Influence of intraocular lens material and design on postoperative intracapsular cellular reactivity.
abstract: OBJECTIVE
  To evaluate the influence of intraocular lens (IOL) material and design on the outcome of postoperative lens epithelial cell proliferation within the capsular bag after cataract surgery.
  
  
  METHODS
  A total of 5,079 human globes containing rigid and foldable posterior chamber IOL styles commonly implanted in the United States (n = 8) were analyzed in this study. Each globe, fixated in 10% formalin, was sectioned at the equator and analyzed using the Miyake-Apple posterior technique. The study consisted of 3 parts: First, to evaluate posterior capsule opacification (PCO); the Nd:YAG laser posterior capsulotomy rate (%) was documented and plotted on a monthly basis, creating a computerized trend line for each IOL style. Second, to evaluate anterior capsule opacification (ACO); 460 globes were processed for histologic examination. Anterior capsule fibrosis was scored from 0 to III, according to the thickness of proliferative tissue/cells on the inner surface of the anterior capsule at the capsulorhexis margin. Third, interlenticular opacification (ILO) was studied by analysis of 3 pairs of acrylic piggyback lenses that had been explanted because of opacification between their optics. Each IOL pair was processed for histologic examination, and scanning electron microscopy was performed on 1 of the lenses.
  
  
  RESULTS
  In the first study, relatively higher Nd:YAG laser posterior capsulotomy rates (19.1% to 32.8%) were noted with the 4 oldest IOL designs in this study (2 foldable lenses, 1 3-piece polymethyl methacrylate [PMMA] design, and 1 single-piece all-PMMA design). Four modern lenses, 1 acrylic lens, and 3 silicone foldable IOL designs had Nd:YAG rates ranging from 1.3% to 14.6% (P < .0001). In the second study, mean ACO scores were highest with silicone-plate lenses (1.77 +/- 0.86 and 1.28 +/- 0.77). The lowest mean score was observed with the acrylic lens (0.51 +/- 0.52; P < .0001). In study 3, the analyses of the 3 pairs of explanted acrylic piggyback lenses showed that the opacification between them (ILO) may have different forms.
  
  
  CONCLUSIONS
  Control of postoperative intracapsular cellular proliferation is important in avoiding 3 significant clinical complications. Postoperative lens epithelial cell proliferation is involved in the pathogenesis of PCO, ACO, and ILO, the latter being a newly described form of opacification within the capsular bag related to piggyback IOL implantation. IOL material and design are important factors influencing the outcome of these complications.
authors.affiliation: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Apple
mesh_terms: D000179:Acrylates / Q000009:adverse effects; D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000209:etiology; D002387:Cataract Extraction / Q000706:statistics & numerical data; D004847:Epithelial Cells / Q000473:pathology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000473:pathology*; D007910:Lenses, Intraocular / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D019904:Polymethyl Methacrylate / Q000009:adverse effects; D011183:Postoperative Complications; D011184:Postoperative Period; D012828:Silicones / Q000009:adverse effects
chemical_list: D000179:Acrylates; D012828:Silicones; D019904:Polymethyl Methacrylate; C036658:acrylic acid