Manchester IStent Study: Early Results from a Prospective UK Case Series

Background: To evaluate the 6-month efficacy and safety of the iStent microtrabecular bypass stent in patients with open-angle glaucoma.

Design: A prospective, uncontrolled, interventional case series.

Participants: Forty-four eyes with open-angle glaucoma were reported.

Methods: All subjects underwent ab interno implantation of a single iStent together with (n = 40) or without (n = 4) cataract surgery.

Main Outcome Measures: Patients were assessed at postoperative week 1, months 1 and 3, and quarterly, thereafter. Data collected included visual acuity, intraocular pressure measurement using Goldmann tonometry, number of glaucoma medications, and number and type of complications.

Results: The mean age of the sample was 76.8 years. The mean duration since glaucoma diagnosis was 5.3 years (standard deviation 2.9 years). The mean visual acuity was 0.53 logMAR at baseline that improved to 0.23 at 6 months postoperatively. The mean baseline intraocular pressure was 21.1 mmHg, and this decreased significantly to 16.7 mmHg at 6 months (P < 0.01). The mean number of drops prescribed preoperatively was 2.3, which decreased to 0.6 at 6 months (P < 0.01). Sixty-six per cent of patients were drop-free at 6 months. One patient developed an hyphaema following surgery; no other adverse events were recorded.

Conclusions: The iStent proved to be a safe and effective treatment for patients with open-angle glaucoma over our 6-month follow up period. Insertion resulted in a significant decrease in intraocular pressure as well as the number of topical antiglaucoma medications required for adequate intraocular pressure control.