The PreserFlo MicroShunt in the Context of Minimally Invasive Glaucoma Surgery: A Narrative Review

Minimally invasive bleb surgery versus minimally invasive glaucoma surgery: a 12-month retrospective study

This study aimed to compare the IOP-lowering effectiveness and safety of standalone Preserflo MicroShunt and iStent 1st generation implantation combined with phacoemulsification in Caucasian patients with a 12-month follow-up period. This retrospective study analyzed the medical histories of patients undergoing antiglaucoma surgery at the Department of Ophthalmology, Medical University of Bialystok, between January 2019 and January 2022. The main outcome measures were success rates (complete: proportion of eyes with IOP < 18 mmHg (criterion A) and < 15 mmHg (criterion B) or 20% reduction in IOP without any glaucoma medication; qualified: proportion of eyes achieving IOPs < 18 mmHg and < 15 mmHg or 20% reduction in IOP from baseline with or without medications), mean reduction (%) in IOP, medication burden, number of complications and additional interventions. In both groups, a significant decrease in IOP and medication burden were observed at 6 and 12 months when compared with baseline. At 12 months, qualified surgical success in criterion A was recorded in 67.4% and 85.7% of patients in the Preserfo and iStent groups, respectively (p = 0.045). Complete surgical success in criterion B at 12 months accounted to 61.4% of patients from Prserflo group and 32.7% patients in iStent group (p = 0.04). Surgical failure at 12 months was documented in 30.2% and 6.3% of patients, respectively (p = 0.003). There was a significant difference between groups in %IOP reduction after 12 months. Greater reduction was observed in Preserflo group, MD = - 8.41 CI95 [- 15.88; - 0.95], p = 0.028, (- 33.49% ± 21.59 vs - 25.07% ± 14.15 in iStent group). Both procedures effectively reduced IOP and postoperative use of antiglaucoma medications in glaucoma patients.

Additional Guidance on the Use of the PRESERFLO™ MicroShunt in the Treatment of Glaucoma: Insights from a Second Delphi Consensus Panel

INTRODUCTION

The PRESERFLO™ MicroShunt (PMS) has been proven to significantly lower intraocular pressure (IOP) in patients with glaucoma and has been available for use since 2019. With increasing published evidence and growing experience of glaucoma surgeons, the aim of this modified Delphi panel was to build on the findings of a previous Delphi panel conducted in 2021 and provide further guidance on the role of the PMS to treat patients with glaucoma in Europe.

METHODS

Thirteen European glaucoma surgeons experienced in the PMS procedure participated in a 3-round modified Delphi panel. A targeted literature review and expert steering committee guided Round 1 questionnaire development. Consensus was pre-defined at a threshold of ≥ 70% of panellists selecting 'strongly agree'/'agree' or 'strongly disagree'/'disagree' for 6-point Likert scale questions or ≥ 70% selecting the same option for multiple or single-choice questions. Questions not reaching consensus were restated/revised for the next round, following guidance from free-text responses/scoping questions.

RESULTS

In total, 28% (n = 9/32), 52% (n = 16/31) and 91% (n = 10/11) of statements reached consensus in Rounds 1, 2 and 3, respectively. There was agreement that the PMS may be used in patients with pigmentary, post-trauma or post-vitrectomy glaucoma and for patients with uveitic glaucoma without active inflammation. The PMS may be more suitable for patients with contact lenses than other subconjunctival filtering surgeries, without eliminating bleb-associated risks. Consensus was reached that combining PMS implantation and phacoemulsification may be as safe as standalone PMS surgery, but further efficacy data are required. Following a late rise in IOP ≥ 4 months post-surgery, topical aqueous suppressant drops or bleb revision may be suitable management options.

CONCLUSIONS

This Delphi panel builds on the considerations explored in the 2021 Delphi panel and provides further detailed guidance for glaucoma surgeons on the use of the PMS, reflecting the availability of novel evidence and surgical experience. Videos are available for this article.

Preventing Blindness with Early Cataract Surgery and Micro-Invasive Glaucoma Surgery in Patients Over 50: Guidance for Patients, Physicians and World Governments in Dealing with Glaucoma

Purpose

To offer clinical guidance and address safety and efficacy concerns regarding the growing use of micro-invasive glaucoma surgery (MIGS) as an initial treatment for glaucoma in adult patients.

Design

Narrative literature review.

Methods

A review was conducted to assess outcomes and complications of MIGS in the treatment of glaucoma, both alone and in combination with lens replacement. These outcomes were compared with those of standard glaucoma surgery and/or glaucoma management with medication.

Results

MIGS are effective at lowering intraocular pressure (IOP) over long periods of follow-up. These techniques share a similarly high safety profile between one another. MIGS were found to have lower complication rates and to be more effective in reducing the total amount of medication needed to maintain control of intraocular pressure than standard surgery approaches.

Conclusion

MIGS techniques are growing in popularity and have been demonstrated to be a safe and effective alternative to standard glaucoma surgery. Guidance in the implementation of these procedures has been outlined.

New Devices in Glaucoma

Glaucoma remains a leading cause of blindness globally. Minimally invasive treatment techniques are rapidly expanding the availability of therapeutic options for glaucoma. These include devices aimed at enhancing outflow through the subconjunctival space, Schlemm's canal, and suprachoroidal space, sustained-release drug delivery devices, and extraocular devices aiming to reduce glaucomatous progression through other novel means. In this review, we provide an overview of several novel devices either newly available or in development for the medical and surgical management of glaucoma. Further studies are required to determine the long-term efficacy of these devices and how they will integrate into the current landscape of glaucoma management.

Minimally Invasive Glaucoma Surgery: A Review of the Literature

Minimally invasive glaucoma surgery (MIGS) has emerged as a novel approach in the glaucoma treatment spectrum, offering a range of diverse procedures and devices aimed at reducing intraocular pressure (IOP). MIGS can be broadly classified into several categories: those that enhance trabecular outflow (Trabectome, iStent, Hydrus Microstent, Kahook Dual Blade, high frequency deep sclerotomy, and gonioscopy-assisted transluminal trabeculotomy), those that augment suprachoroidal outflow (CyPass Microstent and iStent Supra), those that target Schlemm's canal (TRAB360 and the OMNI Surgical System, Streamline, and Ab Interno Canaloplasty), and conjunctival bleb-forming procedures (EX-PRESS Glaucoma Filtration Device, Xen Gel Stent and PreserFlo MicroShunt). MIGS is considered to have a shorter surgical time and fewer severe complications when compared to traditional glaucoma surgeries such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves). This literature review comprehensively examines the distinct MIGS devices and procedures, their underlying mechanisms, and clinical outcomes, emphasizing the importance of evaluating the efficacy and complications of each approach individually. As the field of MIGS continues to evolve, it is crucial to prioritize high-quality, long-term studies to better understand the safety and effectiveness of these innovative interventions in glaucoma management.

One-Year Outcomes of PreserfloTM MicroShunt Implantation versus Trabeculectomy for Pseudoexfoliation Glaucoma

This retrospective, single-center study evaluates the safety and efficacy of Preserflo^TM MicroShunt (MicroShunt) implantations compared to trabeculectomies (TETs) in patients diagnosed with pseudoexfoliation glaucoma (PEXG). A total of 31 eyes from 28 patients received a MicroShunt implantation, and 29 eyes from 26 patients received a TET. Surgical success was defined as an intraocular pressure (IOP) between 5 mmHg and 17 mmHg at the end of the follow-up period, no need for surgical revisions or secondary glaucoma surgery, and no loss of light perception. In the MicroShunt group, the mean IOP dropped from 20.8 ± 5.9 mmHg at baseline to 12.4 ± 2.8 mmHg (p < 0.0001) after one year. In the TET group, the mean IOP dropped from 22.3 ± 6.5 mmHg to 11.1 ± 3.7 mmHg (p < 0.0001) after 12 months. In both of the groups, the mean number of medications was reduced significantly (MicroShunt from 2.7 ± 1.2 to 0.2 ± 0.7; p < 0.0001 vs. TET from 2.9 ± 1.2 to 0.3 ± 0.9; p < 0.0001). Considering the success rates, 83.9% of the MicroShunt eyes achieved complete success, and 90.3% qualified for success at the end of the follow-up period. In the TET group, the rates were 82.8% and 93.1%, respectively. The postoperative complications were comparable between both groups. In conclusion, the MicroShunt implantation demonstrated non-inferiority regarding its efficacy and safety profile compared to TET in PEXG at a follow-up of one year.