A Randomized Trial of a Schlemm's Canal Microstent with Phacoemulsification for Reducing Intraocular Pressure in Open-Angle Glaucoma

Norbert Pfeiffer, Julian Garcia-Feijoo, Jose M Martinez-de-la-Casa, Jose M Larrosa, Antonio Fea, Hans Lemij, Stefano Gandolfi, Oliver Schwenn, Katrin Lorenz, Thomas W Samuelson

Research output: Contribution to journalArticleResearchpeer-review


PURPOSE: To assess the safety and effectiveness of the Hydrus Microstent (Ivantis, Inc, Irvine, CA) with concurrent cataract surgery (CS) for reducing intraocular pressure (IOP) in open-angle glaucoma (OAG).

DESIGN: Prospective, multicenter, randomized, single-masked, controlled clinical trial.

PARTICIPANTS: One hundred eyes from 100 patients 21 to 80 years of age with OAG and cataract with IOP of 24 mmHg or less with 4 or fewer hypotensive medications and a washed-out diurnal IOP (DIOP) of 21 to 36 mmHg.

METHODS: On the day of surgery, patients were randomized 1:1 to undergo CS with the microstent or CS alone. Postoperative follow-up was at 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months. Washout of hypotensive medications was repeated at 12 and 24 months.

MAIN OUTCOME MEASURES: Response to treatment was defined as a 20% or more decrease in washed out DIOP at 12 and 24 months of follow-up compared with baseline. Mean DIOP at 12 and 24 months, the proportion of subjects requiring medications at follow-up, and the mean number of medications were analyzed. Safety measures included change in visual acuity, slit-lamp observations, and adverse events.

RESULTS: The proportion of patients with a 20% reduction in washed out DIOP was significantly higher in the Hydrus plus CS group at 24 months compared with the CS group (80% vs. 46%; P = 0.0008). Washed out mean DIOP in the Hydrus plus CS group was significantly lower at 24 months compared with the CS group (16.9±3.3 mmHg vs. 19.2±4.7 mmHg; P = 0.0093), and the proportion of patients using no hypotensive medications was significantly higher at 24 months in the Hydrus plus CS group (73% vs. 38%; P = 0.0008). There were no differences in follow-up visual acuity between groups. The only notable device-related adverse event was focal peripheral anterior synechiae (1-2 mm in length). Otherwise, adverse event frequency was similar in the 2 groups.

CONCLUSIONS: Intraocular pressure was clinically and statistically significantly lower at 2 years in the Hydrus plus CS group compared with the CS alone group, with no differences in safety.

Original languageEnglish
Pages (from-to)1283-93
Number of pages11
Issue number7
Publication statusPublished - Jul 2015


  • Adult
  • Aged
  • Aged, 80 and over
  • Antihypertensive Agents/administration & dosage
  • Female
  • Follow-Up Studies
  • Glaucoma Drainage Implants
  • Glaucoma, Open-Angle/physiopathology
  • Humans
  • Intraocular Pressure/physiology
  • Lens Implantation, Intraocular
  • Limbus Corneae/surgery
  • Male
  • Middle Aged
  • Phacoemulsification
  • Prospective Studies
  • Prosthesis Implantation
  • Single-Blind Method
  • Stents
  • Tonometry, Ocular
  • Visual Acuity/physiology
  • Visual Fields
  • Young Adult


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