title: A comparison of visual performance between a rigid PMMA and a foldable acrylic intraocular lens.
abstract: OBJECTIVE
  To examine post-operative visual outcomes when using micro-incision surgery and a three-piece, foldable acrylic intraocular lens (IOL) and when using small-incision surgery and a one-piece, rigid polymethyl-methacrylate (PMMA) IOL.
  
  
  METHODS
  Phacoemulsification and IOL implantation was conducted by one surgeon on 86 subjects (aged 50-89 years) with cataracts. Of these subjects, 67 completed the study. Subjects were implanted either with a foldable IOL (n = 38) or a rigid IOL (n = 29). Best corrected Snellen visual acuity and contrast sensitivity (2-28 cycles/degree) were measured approximately 2 months post-operatively. Comparisons were made between the pseudophakic groups and an additional group of 28 age-matched, normal subjects (aged 58-81 years). Non-parametric (Kruskal-Wallis and Mann-Whitney U) as well as parametric (ANOVA and Pearson) statistics tests were used in the analysis of results.
  
  
  RESULTS
  All pseudophakes had corrected visual acuity of 6/9 or better. There were no significant differences in visual acuity (Kruskal-Wallis, p = 0.61) or contrast sensitivity (ANOVA, p = 0.33) between the three groups. The mean residual refractive error of the foldable IOL group was hypermetropic in comparison with the rigid IOL group but not significant at the 99% level of probability (Mann-Whitney U, p = 0.02). There was no significant difference in astigmatism between the groups.
  
  
  CONCLUSIONS
  Implanting a foldable acrylic IOL gave no post-operative benefit in visual acuity and contrast sensitivity to pseudophakes over a less expensive rigid PMMA IOL, within this post-operative period. This study did not provide a comparison between the two lenses regarding post-operative complications, in particular the important long-term complication of posterior capsular opacification (PCO). Until and if any particular advantage of a given IOL in reduced incidence of PCO is confirmed, it appears more economical to implant the conventional rigid PMMA IOL using small-incision surgery.
authors.affiliation: Department Vision Sciences, Glasgow Caledonian University, UK. ajaf@gcal.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: Afsar
authors.forename: S
authors.initials: S
authors.lastname: Patel
authors.forename: R L
authors.initials: RL
authors.lastname: Woods
authors.forename: W
authors.initials: W
authors.lastname: Wykes
mesh_terms: D000180:Acrylic Resins; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015350:Contrast Sensitivity; D006801:Humans; D007910:Lenses, Intraocular; D008875:Middle Aged; D019904:Polymethyl Methacrylate; D011184:Postoperative Period; D011446:Prospective Studies; D019591:Pseudophakia / Q000503:physiopathology* / Q000523:psychology; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity
chemical_list: D000180:Acrylic Resins; D019904:Polymethyl Methacrylate