Mid-term real world outcomes of the Hydrus ® Microstent in open angle glaucoma

Purpose To evaluate the mid-term clinical results and the safety aspects of the Hydrus ® Microstent (Ivantis, Inc, Irvine, CA) in a real-life setting. Design Retrospective case series. Methods Hydrus ® Microstent was implanted in phakic eyes (88 eyes, 87.1%) and in pseudophakic eyes (13 eyes, 12.9%), respectively. Mean follow-up time was 16 ± 9 months with 27 eyes having a follow-up time of more than 24 months. Main outcome measures The primary endpoint was reduction in IOP compared to baseline. Target IOP levels were set at ≤20 mmHg, ≤18 mmHg and ≤15 mmHg. Kaplan–Meier survival was defined as a reduction in IOP of ≥20% compared to baseline. Secondary endpoints were reduction in number of glaucoma medications and safety assessments addressing visual acuity, adverse events, re-surgery rate and identification of factors that made the implantation more difficult. Result 101 eyes underwent Hydrus ® implantation. The mean preoperative IOP was 21.60 mmHg (SD 6.6) on 2.18 (SD 1.3) medications. After a mean follow up time of 16 months, the mean IOP was reduced to 14.61 ± 3.7 mmHg on 1.12 (SD 1.1) medication classes ( p < 0.001). Mean decrease in IOP was 26.7%. Analysis of the target IOP levels showed that in 29%, 34% and 35% of cases an IOP of ≤15 mmHg, ≤18 mmHg and ≤20 mmHg respectively could be achieved. BCVA improved from 0.56 ± 0.3 at baseline to 0.85 ± 0.3 more than 24 months after surgery ( p < 0.001). The rate of re-operation was low at <3%. Adverse events occurred in 4 eyes (<4%). Conclusion This study underlines the effectiveness and the safety of the Hydrus ® Microstent in an elective setting, but it also demonstrates certain limits and risk factors of this procedure.