Minimally invasive glaucoma surgery: comparison of iStent with iStent inject in primary open angle glaucoma

Importance: Minimally invasive glaucoma surgery has gained significant traction in recent years. This study evaluates the first‐ and second‐generation trabecular micro‐bypass stents “iStent” and “iStent inject”.

Background: To evaluate and compare the effect of a single iStent and double iStent inject in primary open angle glaucoma.

Design: Prospective comparative case series.

Participants: Primary open angle glaucoma patients undergoing trabecular micro‐bypass stent insertion combined with cataract surgery.

Methods: Baseline demographic information, preoperative, intraoperative and postoperative outcomes including intraocular pressure (IOP), visual acuity, reliance on glaucoma medication and complications were collected and analysed.

Main Outcome Measures: Primary, secondary and tertiary outcome measures were consecutively defined as an IOP of ≤18 mmHg with zero medications, an IOP of ≤18 mmHg with reduced medications or a 20% reduction in IOP with or without medication.

Results: The study comprised 145 eyes in the iStent and 100 eyes in the iStent inject group. At 12 months, 56.0% of the iStent and 51.3% of the iStent inject eyes had achieved primary success and 63.1% and 57.7% secondary success. The mean postoperative IOP was 16.6 mmHg in iStent and 16.9 mmHg in iStent inject. Survival analysis demonstrated a greater incidence of failure in the iStent inject beyond 5 months.

Conclusions and Relevance: Both trabecular micro‐bypass stents in this study were effective in reducing IOP and the burden of medication when combined with cataract surgery. There was no statistically significant difference between the two groups across our outcome measures although the iStent inject required earlier recommencement of medications for optimal IOP control.