Microstent Implant Can Lower IOP in Mild to Severe Glaucoma

A Schlemm canal microstent implant, paired with cataract surgery, effectively reduces intraocular pressure (IOP) and the number of antiglaucoma medications (AGM) needed in eyes with mild to severe glaucoma, according to findings from a single-surgeon, longitudinal case series published in Ophthalmology Glaucoma. The study shows the device’s efficacy in slowing disease progression at 3 years after implantation.

“An average absolute decrease of 5 mm Hg in medicated IOP was documented, with more than two-thirds of the patients achieving at least 1 medication reduction sustained over the 3-year study period, and a 3-fold increase in medication-free rate,” according to the study.

Patients (N=75; n=106 eyes) with glaucoma who underwent cataract surgery and concurrent implantation with a microstent device at Montreal Glaucoma Institute and Bellevue Ophthalmology Clinics in Canada between 2013 and 2021 were included in this case series. Safety and efficacy of the Hydrus microstent were evaluated at a 3-year follow-up. Surgical success was defined as not requiring additional glaucoma operation or selective laser trabeculoplasty, having no disease progression, maintaining IOP 5 to 18 mm Hg, and not increasing the number of AGM.

The patients were aged mean 70.2±9.7 years at the time of surgery, 58% were men, 63% had primary open angle glaucoma, 30% had mild disease, IOP was 18.4±4.8 mm Hg, and they were taking 3.0±1.2 AGM.

Compared with baseline, IOP had decreased significantly to 13.9±2.3 mm Hg (P <.001) and the number of AGM had decreased to 2.0±1.2 (P <.001) at year 3. At the follow-up, best corrected visual acuity significantly improved from baseline (P =.007).

No changes to mean deviation, pattern standard deviation, cup-to-disc ratio, retinal nerve fiber layer thickness, or ganglion cell and inner plexiform layer thickness were observed at year 3 compared with baseline (all P ≥.681).

Overall, surgical success occurred among 67%. Treatment failure was associated with use of oral carbonic anhydrase inhibitors (hazard ratio [HR], 4.388; 95% CI, 2.027-9.498; P <.001) and baseline IOP (HR, 1.101; 95% CI, 1.028-1.180; P =.006).

No intraoperative adverse events were observed. The most frequent postoperative adverse events included transient microhyphema (14%), early spike in IOP (13%), focal peripheral anterior synechiae in the area of the microstent (12%), and posterior capsule opacification (7%).

“Our cohort achieved a relatively low IOP, which was maintained throughout the 3 years postoperatively with an average of 2 AGMs. Practically speaking, the 2 AGMs can be delivered through once-daily instillation of a  single combination drop containing a prostaglandin analogue and a beta-blocker, thus, potentially helping long-term compliance and quality of life,” study authors explain. “The vast majority of the patients maintained an IOP of ≤18 mm Hg at the 3-year follow-up, with an approximately 8-fold increase in the proportion of patients achieving an IOP of 12 mm Hg and less — a reasonable target pressure strongly desired, especially at the advanced levels of the disease.”

The major limitation of this study was the lack of a comparator cohort.

Disclosure: One study author declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.