Iris-Claw Intraocular Lens: Anterior Chamber or Retropupillary Implantation? A Systematic Review and Meta-Analysis.

Background and Objectives: Iris-claw intraocular lens (ICIOL) could be implanted in the anterior chamber (AC) or retropupillary (RP) in eyes lacking capsular and/or zonular support. Several studies have focused on comparing the efficacy and complications of these two techniques and we designed this research to review the published literatures. Materials and Methods: Peer-reviewed studies were collected through network databases (PubMed, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov) and analyzed. The primary outcome was the standardized mean differences (SMDs) of pre- and post-operative corrected distant visual acuity (CDVA). The secondary outcome was the SMDs of pre- and post-operative intraocular pressure (IOP), endothelial cell counts (ECC), and the odds ratios (ORs) of post-operative IOP elevation and cystoid macular edema (CME). Comprehensive Meta-Analysis software was utilized to conduct statistical analysis. Results: Six studies (one randomized controlled trial and five retrospective case series) were relevant and included a total of 516 eyes (255 and 261 eyes in the AC ICIOL and RP ICIOL groups, respectively). The quantitative analysis showed no significant differences in CDVA (SMD: 0.164, 95% confidence interval (CI): -0.171 to 0.500), ECC (SMD: -0.011, 95% CI: -0.195 to 0.173), and IOP elevation events (OR: 0.797, 95% CI: 0.459 to 1.383). Lesser IOP reduction (SMD: 0.257, 95%CI: 0.023 to 0.490) and a relative increase in the incidence of CME (OR:2.315, 95% CI: 0.950 to 5.637) were observed in the AC ICIOL group compared with RP ICIOL group. Conclusions: Our meta-analysis indicated that AC and RP ICIOL seem to have equivalent visual outcomes. RP ICIOL may perform slightly better with more IOP reduction and lesser CME. More randomized controlled trials, which have higher patient participation and more outcomes are needed to confirm our conclusions.