Objective: To study the influence of square-edged intraocular lenses (IOLs) on the development of posterior capsule opacification (PCO) and the requirement for laser capsulotomy.

Design: Retrospective study.

Participants: Three hundred seventy-seven eyes of 377 patients were included.

Methods: All these patients underwent phacoemulsification and implantation of square polymethyl methacrylate (PMMA) (Aurolab), silicone (Tecnis Z9000), acrylic hydrophobic (AcrySof MA60AC and Sensar Optiedge), or acrylic hydrophilic (Akreos Adapt) IOLs with a minimum of 2 years' follow-up. Only those cases in which Nd:YAG laser capsulotomy had been performed for visually significant PCO were evaluated.

Results: Three hundred seventy-seven eyes of 377 patients were included in the study. Follow-up duration ranged from 24 to 54 (mean 40.27, SD 8.42) months. The incidence of PCO requiring Nd:YAG laser capsulotomy was found to be significantly less in the silicone lens group: 1.4% as compared with an incidence of 11.7% in the PMMA lens group (p = 0.018). In the square-edged acrylic group, visually significant PCO requiring Nd:YAG laser capsulotomy was observed in 3.6%, 4.8%, and 6.8% of eyes implanted with AcrySof MA60AC, Sensar Optiedge, and Akreos Adapt IOLs, respectively. In 5 of the 7 eyes (71.4%) exhibiting PCO in the PMMA group, the condition developed within the first 6 months. In the silicone and acrylic group, development of PCO was delayed.

Conclusions: The rate of visually significant PCO as well as the need for Nd:YAG laser capsulotomy is influenced by IOL biomaterial in addition to square edge. It is significantly delayed with square-edged foldable acrylic and silicone IOLs compared with square-edged PMMA IOLs.