New improved treatment for glaucoma?

Clinical documentation

These new stents are typically made of metal (e.g. heparin-coated titanium) or a soft material (e.g. collagen) which is intended to be biocompatible. These are, nonetheless, a foreign body inside the eye, which in theory could affect nearby structures. However, this has not been sufficiently investigated for most types. One of the most promising stents was withdrawn from the market in 2018 after a study found increased cell loss in the corneal endothelial cell layer at the five-year follow-up (5). This shows the need for thorough safety assessments.

Under the auspices of the Norwegian Institute of Public Health, a health technology assessment (HTA) was performed in 2021. The conclusion in the HTA report was as follows (6): 'The clinical evidence on MIGS is limited. The main reason for this is the lack of comparative studies.' The HTA further found that these technologies 'may be cost-effective, depending on comparator and disease stage.'. The report predicts that the number of such procedures will double by 2024. We believe that the increase will be considerably higher.

The Preserflo MicroShunt (Santen) is one type of MIGS that is increasingly being used in Norway and other countries. It is made from a biocompatible synthetic polymer material and has shown promising results in the few long-term studies that have been conducted (7). The results of a recently published randomised multi-centre study also suggest that the stents are effective even when being compared to traditional glaucoma surgery (trabeculectomy) (8). In Norway, other types of stents have also been used, including the XEN gel stent and the iStent. Clinical documentation is limited for most types of MIGS and more studies are now needed.

Preliminary clinical experience and the limited data give reason for cautious optimism

There are strong indications that MIGS is here to stay. Preliminary clinical experience and the limited data give reason for cautious optimism. We believe that MIGS has the potential to make a marked change in the treatment options for this patient group. The cost per stent is high, but cost-effectiveness will depend on the long-term effectiveness, the need for postoperative follow-up and additional surgery, and the proportion of patients who manage without glaucoma medication. More research and quality improvement studies will provide a better basis for assessing effectiveness and safety, and for drawing up guidelines for glaucoma treatment – which must also include MIGS.