The effect of polymethylmethacrylate, silicone, and polyacrylic intraocular lenses on posterior capsular opacification 3 years after cataract surgery

Ophthalmology. 1999 Jan;106(1):49-54; discussion 54-5. doi: 10.1016/S0161-6420(99)90047-7.


Objective: To compare the visual outcome, neodymium:YAG (Nd:YAG) capsulotomy rates, and percentage of posterior capsular opacification (PCO) seen with polymethylmethacrylate (PMMA), silicone, and polyacrylic intraocular lens implants 3 years after surgery.

Design: Randomized, prospective trial.

Participants: Ninety eyes of 81 patients were examined at a British teaching hospital.

Intervention: Ninety eyes were prospectively randomized to receive a PMMA, silicone, or polyacrylic (AcrySof, Alcon, Fort Worth, TX) implant. All lenses had 6-mm disc optics with PMMA haptics. A standardized surgical protocol was performed by a single surgeon using an extracapsular technique with capsulorhexis; any surgical complications were excluded and all patients had standardized postoperative medication and follow-up.

Main outcome measures: Patients were seen at 6 months and 1, 2, and 3 years after surgery. At 3 years, logarithm of the minimum angle of resolution (LogMAR) visual acuity and Pelli-Robson contrast sensitivity were measured and YAG capsulotomy rates determined. Posterior capsular opacification was assessed objectively by digital retroillumination imaging using dedicated software and calculated as the percentage area of opacified capsule.

Results: At 3 years, the overall follow-up rate was 71%: 19 patients were available for examination with polyacrylic lens implants, 22 with silicone, and 23 with PMMA. There was a significant difference in percentage PCO at 3 years among the lens types (P = 0.0001). Polyacrylic lenses were associated with less PCO (10%) than silicone (40%) and PMMA lenses (56%). The YAG capsulotomy rate was 0% for polyacrylic, 14% for silicone, and 26% for PMMA (P = 0.05). The visual acuity and contrast sensitivity were not significantly different among the three groups if patients with age-related macular degeneration and those requiring YAG capsulotomies are excluded.

Conclusions: Intraocular lenses made from polyacrylic are associated with a significantly reduced degree of PCO and lower YAG rates.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylates / adverse effects*
  • Aged
  • Aged, 80 and over
  • Capsulorhexis*
  • Cataract / etiology*
  • Cataract / pathology
  • Contrast Sensitivity
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Lens Capsule, Crystalline / pathology*
  • Lens Implantation, Intraocular
  • Lenses, Intraocular / adverse effects*
  • Male
  • Middle Aged
  • Polymethyl Methacrylate / adverse effects*
  • Prospective Studies
  • Silicone Elastomers / adverse effects*
  • Visual Acuity


  • Acrylates
  • Silicone Elastomers
  • Polymethyl Methacrylate