Comparing iStent versus CyPass with or without phacoemulsification in patients with glaucoma: a meta-analysis

Bacground: The aim of this study was to conduct a meta-analysis to compare the overall intraocular pressure (IOP)-lowering effect of iStent or CyPass as isolated procedures or in combination with cataract extraction. Materials and methods: Cochrane review manager 5.3 software (RevMan((R)) 5.3) was used for a meta-analysis of IOPs and the number of antiglaucoma medications in six groups according to the type and number of stents and whether the procedure was isolated or in combination with cataract extraction. Main results: A total of 33 out of 446 publications retrieved have been enrolled. The mean changes in IOP in the groups with one iStent and more than two iStents with concurrent cataract extraction were -3.78 +/- 0.53 mmHg and -3.89 +/- 0.73 mmHg, respectively. The mean differences in IOP in the groups with one iStent and more than two iStents without concurrent cataract extraction were -3.96 +/- 0.25 mmHg and -7.48 +/- 0.55 mmHg, respectively. The mean changes in IOP in the groups with CyPass implantation with and without concurrent cataract extraction were -4.97 +/- 1.38 mmHg and -8.96 +/- 0.16 mmHg, respectively. Conclusions: Both iStent and CyPass either in combination with cataract extraction or as isolated procedures effectively decrease IOP. This effect is greatest with isolated implantation of CyPass followed by multiple iStents and then single iStent implantation and lasts up to 2 years.