MicroShunt Offers Sustained Reduction in IOP in Patients With Glaucoma

Implantation of the MicroShunt, a minimally invasive bleb surgery (MIBS), would be able to reduce intraocular pressure (IOP) in the long term for patients with glaucoma, according to a new study published in Graefe’s Archive for Clinical and Experimental Ophthalmology.¹ These results offer new evidence of a treatment option for patients living with glaucoma.

Glaucoma is one of the leading causes of blindness in the world, with the reduction of IOP being the chief method of treating the condition. Surgery to treat glaucoma is often used when the condition is in its advanced stage,² with trabeculectomy being a key method of treating glaucoma. However, with the complications possible after this surgery, MIBS has been developed to potentially offer safer methods of addressing IOP. This study aimed to evaluate the 6-year efficacy of the MIBS treatment, MicroShunt, in 1000 eyes to determine if it could effectively reduce IOP in those living with glaucoma.

The study took place in a single center, with participants included if they had the MicroShunt implanted between January 2019 and May 2025. Patients were separated into 3 groups, where the first group consisted of all eyes that have undergone MicroShunt surgery, the second group of eyes that had combined cataract with MicroShunt surgery, and the third group, eyes that were pseudophakic before implantation of the MicroShunt.

Patients could be included in the study if they had uncontrolled IOP, increased medication burden, or insufficient compliance. The patients needed to have 6 months of follow-up as well. Demographic features, severity of glaucoma, and glaucoma type were all extracted before the operation. IOP change from baseline, reduction in medications, complication rates, and complete or qualified success were the primary outcome measures of the study.

There were 1001 eyes from 673 participants that were included in the study and received a MicroShunt. Pseudophakic eyes made up 513 of the eyes that received MicroShunt surgery alone. The mean (SD) age of the participants was 70 (11) years, and 44% of the eyes were from men. The majority of the participants were White (97%) and had either primary open angle glaucoma (69%) or pseudoexfoliative glaucoma (27%). The majority of the participants had not had glaucoma surgery(71%).

The mean IOP was 24.8 (8.4) mm Hg in all eyes before the operation. Mean IOP was reduced to 9.6 (4.4) mm Hg in all eyes 1 day after the operation. These results were sustained through 1 year, as the mean IOP was 13.2 (3.9) mm Hg in all eyes at the 1-year follow-up, and were maintained through 4 years, where the mean IOP was 13.7 (3.1) mm Hg in all eyes. Scatter plots found that those with higher IOPs before the operation had a greater absolute reduction in IOP.

Complete success was 54% after 4 years when using a target of 6 to 21 mm Hg and 45% with a target of 6 to 18 mm Hg; only 8% achieved complete success with a target of 6 to 14 mm Hg. Qualified success was higher after 4 years, with 68% reporting qualified success with a 6-to-21 mm Hg target and 53% reporting qualified success with a target of 6 to 18 mm Hg. The mean number of medications was also reduced from 2.41 (1.14) before surgery in all eyes to 0.29 (0.76) after 4 years in all eyes.

There were some limitations to this study. Selection and information bias was possible due to the retrospective nature of the study. Intrapatient correlation between fellow eyes was not modeled for this study. Visual field progression and endothelial cell density were not analyzed for this study, which could have limited conclusions for long-term outcomes.

The authors concluded that “the MicroShunt is effective and offers durable and safe long-term IOP control and a clinically relevant reduction in medication use.” This study is able to contribute real-world data for pseudophakic eyes and in eyes that underwent both cataract and MicroShunt surgery to establish the efficacy of the glaucoma treatment.

References

1. Klabe K, Werth JP, Kaymak H, Fricke A. Clinical outcomes of Preserflo Microshunt implant procedure in open-angle glaucoma patients – a 1000 eyes case-series; including subanalysis of combined cataract-glaucoma surgery and standalone surgery in pseudophakic eyes. Graefes Arch Clin Exp Ophthalmol. Published online March 28, 2026. doi:10.1007/s00417-026-07199-z
2. Glaucoma. Cleveland Clinic. Updated November 12, 2024. Accessed March 31, 2026. https://my.clevelandclinic.org/health/diseases/4212-glaucoma