Untitled design

One Million iStent Implants: Looking Forward and Backward

Minimally invasive glaucoma surgery (MIGS) might be minimally invasive to patients, but they’re maximally changing the world of glaucoma management. So, we’re here to bring you some big news from the MIGS world: The iStent® (Glaukos, California, USA) has reached 1,000,000 implants! The number marks a significant milestone for doctors and patients alike, many of whom have been profusely proselytizing the product.

We were lucky enough to catch up with one top ophthalmologist who’s integrated the iStent into her practice and noted its success. This is none other than Prof. Tina Wong, head of glaucoma service at the Singapore National Eye Centre (SNEC). Prof. Wong has been performing MIGS surgeries since the very beginning over the last decade. She spoke with us about how the iStent has improved the lives of her patients and just what the new milestone means.

The word about iStent technology has certainly been spreading. But wait a tick — just what’s going on here? Where does the iStent inject W (iStent) fit in — in glaucoma treatments — and what makes it special?

The MIGS sweet spot

Figuring out just where and how the iStent plays a role in glaucoma treatment is up to each surgeon, but there seems to be a sweet spot. For Prof. Wong, that’s between eye drops and conventional surgery. As she noted, if a patient is having a cataract removed and has mild to moderate glaucoma, the iStent would be a good option. Patients who have a heavy medication burden could also be well served by the iStent, as it reduces intraocular pressure (IOP).

There are lots of MIGS options, though. So what’s so great about the iStent?

Explained Prof. Wong: “It’s really about the device speaking for itself. People see the results, they’re happy — they spread the word. The ambassadors are the doctors and the patients. The company has done the marketing, but the marketing is also through the end users. I think that’s really where they’ve hit the sweet spot: They’ve been able to get a really good device that’s worked very well… so that’s why they’ve been able to hit the million mark really quickly.”

When MIGS first hit the scene, many doctors were curious just how it was going to fit into their treatment portfolio. Would it replace conventional surgeries, or would it make for an addition? From what we can see now, MIGS devices like the iStent offer more options to doctors and patients alike — adding to choices rather than subtracting, which is valuable in a personalized condition like glaucoma.

Quality of life

There are few better ways to measure the outcomes of medical interventions than a patient’s quality of life. And the iStent has had solid results: Indeed, a 12-month study of the iStent implanted in Asian eyes led to a 10-15% increase in quality of life.¹ For one little MIGS, we think that’s a pretty big deal.

That was just a pilot study, but the results were positive enough to lead to a much larger study soon to begin. There’s still much more to be learned about Asian eyes in regard to glaucoma and the iStent, specifically. For example, around 50% of Asian glaucoma patients have angle closure, which means much higher rates than the rest of the world.

The new generation of MIGS coming through, including further iterations of the iStent, will help surgeons improve more lives than ever before.

Freedom from medication

Quality of life is always a subjective term, so let’s take a look at just what that means for patients. How exactly does the iStent help improve a patient’s quality of life?

As Prof. Wong noted, “I think it’s liberating for patients when they do not have to use eye drops. That’s the bottom line.” When patients are offered the opportunity to get off eye drops, most of them will simply say, “Yes, please.”

In a pivotal trial of iStent inject® implanted at the time of cataract surgery, it was observed that 84% of patients were medication-free at 23 months.2

Integrating the iStent

Ease of use and smooth integration are crucial for any implant or surgical procedure to take off. That certainly seems to be the case with the iStent, which is good news for doctors looking to integrate it into their service. As Prof. Wong put it, “The iStent was very easy to use. Being a glaucoma specialist, I’m used to performing gonioscopies. So identifying the anatomy of the anterior chamber angle — where to place the device — was already naturally there.”

She continued: “To implant it just took a few times to get used to it, and after that it was pretty smooth. Following up on my patients, they all seem to have done well. I’m becoming more and more confident.”

Looking forward

The iStent is basically a household name among glaucoma specialists now and has become a regular tool in glaucoma management. That’s pretty neat, especially considering how new it is. And it’s going to continue to evolve.

We can’t wait to hear what’s next in the not-so-little world of MIGS, where things move fast. Better options for patients and doctors mean better vision and happier people. Now, there’s something to look forward to.

iStent inject® Important Safety Information

INDICATION FOR USE: The iStent inject® W Trabecular Micro-Bypass System (Model G2-W) is intended to reduce intraocular pressure in adult patients diagnosed with mild to moderate primary open-angle glaucoma (POAG) currently treated with ocular hypotensive medication. The device can be implanted with or without cataract surgery.

CONTRAINDICATIONS: The device is contraindicated for use in eyes with primary angle closure glaucoma, or secondary angleclosure glaucoma, including neovascular glaucoma, because the device would not be expected to work in such situations, and in patients with retrobulbar tumour, thyroid eye disease, Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure.

WARNINGS: This device has not been studied in patients with uveitic glaucoma. Patients should be informed that placement of the stents, without concomitant cataract surgery in phakic patients, can enhance the formation or progression of cataract.

The surgeon should monitor the patient postoperatively for proper maintenance of intraocular pressure. iStent inject is MRConditional, meaning that the device is safe for use in a specified MRI environment under specified conditions; please see labelling for details. Physician training is required prior to use. Do not re-use the stent(s) or injector.

ADVERSE EVENTS: Postoperative adverse events include but are not limited to: corneal complications including edema, opacification and decompensation, cataract formation (in phakic patients), posterior capsule opacification, stent obstruction, intraocular inflammation (non-pre existing), BCVA loss and IOP increase requiring management with oral or intravenous medications or surgical intervention. Please refer to Directions for Use for additional adverse event information.

CAUTION: Please reference the Directions For Use labelling for a complete list of contraindications, warnings and adverse events.


  1. Ang BCH, Chiew W, Yip VCH, et al. Prospective 12-month outcomes of combined iStent inject implantation and phacoemulsification in Asian eyes with normal tension glaucoma. Eye Vis (Lond). 2022;9(1):27.
  1. Berdahl J, Voskanyan Lilit, Myers JS, et al. Implantation of two second-generation trabecular micro-bypass stents and topical travoprost in open-angle glaucoma not controlled on two preoperative medications: 18-month follow-up. Clin Exp Ophthalmol. 2017;45(8):797-802.

Editor’s Note: This article was published in CAKE Magazine Issue 18.

Prof. Tina Wong

Prof. Tina Wong, MBBS, FRCS(Ed), FRCOphth, FAMS, PhD (Lond), is the head and senior consultant of the Glaucoma Department at Singapore National Eye Centre (SNEC). She was trained at the Moorfields Eye Hospital (London, United Kingdom). Prof. Wong heads the Ocular Therapeutics and Drug Delivery Research Group at the Singapore Eye Research Institute SERI). Also, she holds an adjunct faculty appointment at the National University Hospital System (NUHS) and is the Executive Director of the National Health Innovation Centre, NMRC. Development of new ophthalmic therapies, nanomedicine and the innovative application of drug delivery systems to improve on the current medical and surgical treatments in glaucoma and other ophthalmic diseases, are among Prof. Wong’s research interests. She has published widely in these areas and has nationally funded research grants amounting to $8M. She holds many patents to her name and is the co-founder of two spin off biotech companies that spawned from her research. Furthermore, Prof. Wong has presented at numerous international scientific and ophthalmological meetings. She has been invited as a speaker at international conferences and also at academic institutes and universities. Prof. Wong is the founding president of the Glaucoma Association of Singapore (GLAS), a member of the World Glaucoma Association (WGA), and examiner to the Royal College of Edinburgh of Surgeons (Ophthalmology), United Kingdom.[Email: tina.wong.t.l@singhealth.com.sg]

Notify of
Inline Feedbacks
View all comments