The Burden of Proof
The glaucoma subspecialty is now at a turning point. But new approaches, including MIGS, must be based on high-quality evidence – and that means more randomized controlled trials.
The “gold standard” of glaucoma treatment – trabeculectomy – is anything but golden. Although the procedure is 60 years old, it has largely remained unchanged, despite many attempted modifications. It is a type of surgery no ophthalmologist looks forward to performing, as its outcomes are very unpredictable – there are a host of possible early and late complications, which can be devastating for the patient.
When MIGS devices were first introduced, the idea was to provide a surgical procedure that is much safer than trabeculectomy, but has at least modest efficacy. A change of mindset was needed: suddenly we weren’t necessarily aiming for maximum efficacy, but for maximum safety.
Glaucoma specialists are a conservative group – and extremely data-driven when it comes to new treatment options – so we didn’t all throw ourselves straight into the surgical innovation pool. I am speaking in general terms when I say that “we” expect to see pilot studies, case studies, and a great deal of prospective data; of course, there are always pioneers who are prepared to take some risks.
The discussion at glaucoma meetings over the last five years has been focused on whether MIGS devices are just a fluke – a novelty that will fade and leave no trace – or if they were here to stay.
In my opinion, 2019 was the first year when the tone of these discussions shifted. Most of the controversy about using MIGS devices seems to have been left behind, as we now have a growing body of evidence to confirm that i) MIGS devices are safe, ii) procedures are easy to perform and can be done in an ambulatory setting, so the specialist’s time is reduced, iii) patients’ quality of life is improved as the recovery process is fast, and iv) the devices are at least modestly efficacious. These points have been nicely summarized in the World Glaucoma Association’s 2019 Consensus Series Book on glaucoma surgery.
That last aspect largely depends on the surgeon’s skills and experience, and the patient’s specific needs: for one patient, requiring just one regular medication is a great outcome; for another – who might be suffering from chronic dry eye – stopping medication altogether will be the improvement in their quality-of-life that they want to see.
What we are still lacking is the highest level of evidence: randomized controlled trials (RCTs), comparing MIGS outcomes with the glaucoma gold standard. These trials are not exactly forthcoming: there are still very few quality MIGS RCTs. And they might only be applicable to a specific patient setting or population.
If there isn’t a huge body of evidence available, the results might be skewed by the surgeon’s bias, preference, or level of experience. And that’s why we need more high-quality, quantified data from RCTs – and relating to various MIGS devices available on the market – which can be independently reviewed in a large volume. Thankfully, device manufacturers realize this as an imperative, and we are seeing an increase in RCT numbers in the MIGS field.
We live in an era of constant change in glaucoma, and it is vitally important to adapt our practice to current procedures – and let the datasets change our mindsets and guide our clinical decisions. Pioneering work is important, but we should always be mindful of any adverse effects of novel treatments that we hear about. Now is the time to truly focus on acquiring and consolidating as much data on MIGS as we can, and coming up with universally-accepted standards and guidelines towards a new “gold standard” for glaucoma.
Relevant disclosures
Santen (C), Fabrinal (C), Alcon (S), Allergan (S), Optovue (S); ImplanData (C), New World Medical (C), Oertli (C)
