Real-World 4 And 5-Year Outcomes For Patients Treated With The Istent Inject (G2) Minimally Invasive Glaucoma Surgery Device

To report the 4 and 5-year long-term real-world outcomes of the iStent Inject (G2) device.

Single Centre, Retrospective Case Series, at Queen Elizabeth Hospital, Birmingham, UK.

An automated algorithm was used to extract baseline and follow-up data for patients undergoing iStent implantation with or without cataract surgery. As experience was gained with the iStent, the baseline glaucoma severity criteria for use of the device were relaxed. Therefore, the results are presented as 2 cohorts. There were 50 eyes (38 patients) with 5-year data (cohort 1) and 59 eyes (47 patients) with 4-year data (cohort 2).  Most cases were combined with cataract surgery.  Outcome measures were Intraocular Pressure (IOP), number of medications to control IOP, Visual Acuity (VA), and Mean Deviation (MD) on Humphrey 24-2 Visual Field testing.  The study was registered as a clinical audit.

For cohort 1, mean IOP (mean number of medications) were as follows: Baseline 20.1mmHg (2.4); 6 months: 14.1 (1.7); 12m: 14.2 (1.6); 24m: 15.1 (1.6); 36m: 14.3 (1.8); 48m: 14.9 (1.7); 60m: 14.7 (1.7) p<0.001 for IOP (-5.4mmHg) and medication (-0.7) reduction at 5 years. For cohort 2: Baseline: 17.1mmHg (1.5); 6m: 13.9 (0.9); 12m: 13.1 (1.1); 24m: 15.5 (1.0); 36m:14.4 (1.2); 48m: 14.2 (1.2) p<0.001 for IOP (-2.9mmHg) and p=0.016 for medication (-0.3)
reduction at 4 years.

Mean VA at baseline compared with final follow-up improved from 0.25 logMAR to 0.13, n=109 eyes (71 patients), p=0.008.

Average MD improved from -9.63dB at baseline to -8.29dB at a minimum of 3.5 years follow-up (n=78 eyes, 53 patients, with reliable visual fields, p=0.025).

In this real-world study, the iStent inject in combination with cataract surgery demonstrated a concomitant reduction in IOP and medication burden in 109 eyes (71 patients) through 4 and 5 years. This was achieved in 2 distinct cohorts with higher and lower mean baseline pressures and medication level and with significant glaucoma (mean baseline MD of -9.63dB). Visual acuity and MD improved due to the combined cataract surgery. These results were sustained through 4 and 5 years, demonstrating that the iStent inject is a safe and effective device for the long-term treatment of glaucoma in real-world patients.