Researchers recently evaluated 1-year efficacy and safety data for the Preserflo MicroShunt in primary open-angle glaucoma, including its high-pressure and normal-pressure variants. They found significant intraocular pressure reduction and medication burden relief with no severe complications.

In the prospective, single-center interventional case series, researchers included 42 White/European patients with primary open angle glaucoma (POAG). Twenty-nine patients had high-pressure glaucoma (HPG) and 13 had normal-pressure glaucoma (NPG). Mitomycin C-augmented Preserflo MicroShunts were implanted in standalone procedures (0.2 mg/mL for 3 minutes). Primary outcomes were mean diurnal intraocular pressure (mdIOP), peak IOP, IOP fluctuation, and medication use at 12 months; while secondary outcomes included visual acuity, visual fields, complications, and adverse events.

“Many studies have already demonstrated the effective and safe IOP-lowering with substantial reduction of antiglaucoma medication after Preserflo MicroShunt implantation in POAG, pseudoexfoliation glaucoma, and glaucoma refractory to previous subconjunctival surgery or refractory uveitic glaucoma. However, the outcomes in patients with NPG, a subset of open angle glaucoma characterized by glaucomatous damage despite having a pretherapy IOP within the normal range, remain understudied and available data are limited,” the study authors explained in their recent Journal of Glaucoma article.

In their analysis, they found the following levels of IOP reduction:

• HPG Group: mdIOP decreased by 30% from 16.5 mmHg to 12.8 mmHg (P < .001).
• NPG Group: mdIOP dropped by 40% from 14.3 mmHg to 9.5 mmHg (P = .001).
• Peak IOP Reduction:
  • HPG: 22.0 mmHg to 15.0 mmHg (P < .001).
  • NPG: 17.0 mmHg to 12.0 mmHg (P = .001).

IOP fluctuation was reduced by 43% in the HPG group and 17% in the NPG group.

“In fact,” the study authors reported, “nine NPG eyes (70%) had single-digit mdIOPs without any need for antiglaucoma medication during the first year.”

Most (92.5%) eyes were medication-free at 12 months compared with 0% preoperatively. The patients in both groups reduced their medication use from four to zero (HPG P < .001, NPG P = .005).

No severe adverse events (eg, vision loss, corneal decompensation, or infection) occurred. Almost half (47.5%) of the patients experienced transient hypotony (≤ 5 mmHg), which resolved without intervention in most cases. Bleb encapsulation occurred in five cases (12.5%) and required successful needling. There were no cases of microshunt migration, erosion, or endophthalmitis. The researchers noted that an intraluminal suture to avoid early hypotony could be considered, though consensus regarding the level of IOP or bleb configuration that is optimal for suture removal is unclear. They did not recommend routine stenting of all eyes.

Limitations of the study included a short follow-up period, homogeneity of a single-center population, and lack of medication washout period. Nonetheless, the “high efficacy and the favorable safety profile, as well as the less traumatic approach and smooth postsurgical care with less follow-up visits needed compared with trabeculectomy, present a positive benefit-to-risk ratio so that the MicroShunt implantation may be recommended earlier in the treatment of POAG and probably also in eyes with NPG,” the study authors concluded.

A full list of disclosures can be found in the published research.