The iStent (Glaukos Corporation, Laguna Hills, CA, USA) is one of the minimally invasive glaucoma devices. It can be inserted at the time of phacoemulsification or as a stand-alone procedure to lower the intraocular pressure.
Our aim is to conduct a systematic review and meta-analysis comparing the effect of iStent insertion at the time of phacoemulsification with phacoemulsification alone in patients with ocular hypertension or open-angle glaucoma. Methods We searched EMBASE, MEDLINE (OVID and Pubmed), CINAHL and Cochrane Library for articles published between 2008 and June 2022(PRISMA 2020 for checklist). Studies comparing the IOP lowering effect of iStent with phacoemulsification versus phacoemulsification alone were included. The endpoints were the reduction in IOP (IOPR) and the mean reduction in number of glaucoma drops. A quality-effects model was used to compare both surgical groups. Results 10 studies were included, reporting on 1,453 eyes. 853 eyes had the combined iStent and phacoemulsification, and 600 eyes underwent phacoemulsification alone. IOPR was higher in the combined surgery at of 4.7 ± 2. mmHg compared to 2.8 ± 1.9 mmHg in phacoemulsification alone. A greater decrease in post-operative eye drops was noted in the combined group having a decrease of 1.2 ± 0.3 eye drops vs of 0.6 ± 0.6 drops in isolated phacoemulsification. Quality effect model showed an IOPR weighted mean difference (WMD) of 1.22 mmHg (CI: [-0.43, 2.87]; Q=315.64; P<0.01; I2=97%) and decreased eye drops WMD 0.42 drops (CI: [0.22, 0.62]; Q=42.6; P<0.01; I2=84%) between both surgical groups. Subgroup analysis shows that the new generation iStent may be more effective in reducing IOP. Conclusion iStent has a synergetic effect with phacoemulsification. The reduction of IOP and glaucoma eye drops was higher when iStent is combined with phacoemulsification compared with isolated phacoemulsification.

The Author(s). Published by S. Karger AG, Basel.