The Glaucoma Goldilocks Zone

How the iStent inject® represents a procedure that may be “just right” for many glaucoma patients

06/05/2020

sponsored by Glaukos

In the past, if a glaucoma patient suffered from cataracts, there were two available options. The first was to simply perform cataract surgery and to keep treating the patient for glaucoma; only sometimes would there be an opportunity to decrease treatment – or remove one drug or better control the intraocular pressure (IOP). The other option was to combine cataract and glaucoma surgery in patients with severe glaucoma; however, this double surgery carried an increased likelihood of complications.

Enter the iStent inject® W…

The procedure is designed to bypass the trabecular meshwork, increasing fluid outflow through the canal while minimising the risk of hemorrhage and severe hypotony seen with other glaucoma surgeries.

It offers an alternative that can be used either in mild to moderate patients, where there is the opportunity to reduce or remove topical treatments (at the discretion of an eye doctor), or where the technique can be combined with topical medication to stop progression of the disease and avoid filtering surgery. The procedure is elegant – with a comparatively short learning curve – and integrated well with cataract surgery. Surgeons can therefore experience efficiency in surgical time, spare complications, and save on complication-related costs (1, 2, 3).

Christophe Baudouin, Professor of Ophthalmology, chairing the department at Quinze-Vingts National Ophthalmology Hospital in Paris, France, answers some questions about using the iStent inject from Glaukos for combined procedures.

Why is it so important to reduce topical medications in glaucoma patients?

Though only around 15 percent of the general population are diagnosed with ocular surface disease (OSD), over 70 percent of glaucoma patients have OSD symptoms (4). Localized glaucoma treatments can cause patients to develop OSD, and that risk of developing OSD increases with the number of medications and the duration of treatment. No procedure will be sufficient if the surface of the eye is damaged, so it is crucial to intervene before glaucoma has advanced.

Combined cataract and iStent inject W surgery can help improve quality of life for glaucoma patients by reducing or potentially removing the burden of eye drops and their associated side effects. The number of patients successfully off drugs depends on the number of medications they were taking before – and the level of IOP. If the patient is able to control their IOP before surgery with one or two drugs, I have found that they are likely to be medication-free after surgery. Even with more moderate to severe glaucoma patients, it’s still quite common for them to be off treatment altogether, or to at least be using fewer medications post-op – a significant improvement for both the ocular surface and patient quality of life.

What could you tell us about the safety and efficacy of the iStent inject W?

Above all, the iStent inject W commands recognition for its safety – this minimally invasive glaucoma surgery (MIGS) can increase the effect of cataract surgery on IOP control, while maintaining a safety profile similar to cataract surgery. iStent inject W is an elegant procedure that can be carried out by a single surgeon and requires little additional time to perform in comparison with standard cataract surgery. The procedure means there is no ablation, no trabecular scarring and no need for conjunctival management.

Importantly, implanting iStent inject W is elegant procedure, and there is no need to change the protocol of cataract surgery at all. Combined with its safety profile, this can enable surgeons to avoid delaying glaucoma surgery and associated IOP control. In my experience it appears to be very comfortable for the patient and it doesn’t have an impact on their visual acuity (5), my choice of IOL, or even on my standard follow-up for cataract surgery. However, because these are glaucoma patients, IOP must of course be monitored after the surgery so that treatments can determined for each individual.

How long have you been using the iStent inject? What has your experience been like?

As one of the first ophthalmologists to use the iStent, I have now been performing the procedure for over 10 years. For me, this is the best evidence in favor of the technique, as we too often see procedures abandoned after a few years once a risk appears.

The iStent inject truly fulfils an unmet need for so many of my patients. In cases of moderate glaucoma or glaucoma that is progressing, I offer combined cataract surgery with the iStent inject. There are also certain cases where I will want to remove treatments, and cataract surgery alone would not be enough. Personally, I find a lot of patients are in this intermediate position, where the ultimate aim is to decrease the burden of medication and to preserve the ocular surface. In cases where glaucoma is progressing slowly after IOP restoration and it is necessary to perform situational therapy in a few years, an improved ocular surface is a massive advantage in terms of patient prognosis; all the data on glaucoma surgery confirm that the better the ocular surface, the better the outcome of surgery. If at the time of cataract surgery, you can improve the surface by decreasing the number of medications, it has a prominent effect not only on the comfort of the patient, but also on the future of glaucoma care.

David Antolin, Medical Director of Central Ocular, Madrid, Spain

What is your experience with iStent inject?

For the last 15 years, I have been performing extensive glaucoma surgery for both public teaching hospitals and private practice. My main glaucoma option is non penetrating deep sclerectomy (NPDS); however, the iStent inject has gained a significant place in my portfolio for specific patients, including those with OSD, only-eye patients, drug intolerants, non-compliant patients, those prone to bleb complications, and elderly patients.

When speaking to patients or surgeons about iStent inject, my main argument is not so much “what I do expect” but rather “what I do not expect” – in other words, I am confident we can avoid the typical post-op complications of other surgeries. I have found this technique particularly useful for uncontrolled patients whose personal or professional circumstances mean regular glaucoma surgery would be unacceptable – the potential for months of blurred vision, early reoperations or other side effects will simply not be tolerated.

In these cases, iStent inject offers a minimally invasive technique with excellent tolerance and vir tually absent post-op disturbances (6). Because of its benign post-op experience and comfort, the iStent inject has also been great for patients who are reluctant to undergo surgery because of a previous bad experience.

How easy is it to incorporate into a practice?

The iStent inject is an elegant procedure, straightforward to perform, has little evidence of complications (6), and requires no expensive investments. It can therefore be introduced into a busy surgical routine without interruption. iStent inject does not have the potential to lower IOP as much as a trabeculectomy for example, but patients who need a trabeculectomy are not the patients we indicate for iStent inject – p atient s election is key with trabecular micro-bypass surgery. Also, I believe the cost of the iStent can be balanced by the absence of associated expensive equipment, the efficient surgical turnover, the lack of a need for a second surgeon, the lack of postoperative complication or reintervention costs, the reduced chair time, and the minimal postoperative procedures and consultations (1, 2, 7, 8, 9).

Overall, it is my opinion that the iStent inject is a procedure which is low-risk (6), elegant, and can significantly improve the quality of life for my glaucoma patients by controlling IOP without (or with a lower number of) medications (10), which improves quality of life for patients suffering from OSD, in most cases, while potentially delaying or avoiding the need for more invasive techniques.

Subspecialties Glaucoma

Cost-utility analysis of iStent inject for the treatment of mild to moderate open-angle glaucoma in Norway – Technical report and Model January, 2019. Data on File.
T Jones et al., "A UK Cost Analysis of iStent ® in Patients with Open-Angle Glaucoma from an NHS Commission Perspective". Poster presentation by Leon Au. ICGS, Montreal 6-8 Sept 2018.
PM Buchholz et al., "Budget impact analysis of trabecular bypass stenting versus trabeculectomy for the treatment of open-angle glaucoma from a German payer perspective". Poster presented at ARVO Feb 2019.
AL Mylla Boso et al., “Impact of Ocular Surface Disease Treatment in Patients with Glaucoma”, Clin Ophthalmol, 14, 103 (2020). PMID: 32021047.
AS Ioannidis et al., “Refractive outcomes after trabecular micro-bypass stents (iStent inject) with cataract extraction in open-angle glaucoma”, Clin Ophthalmol, 14, 517 (2020). PMID: 32158184.
RAP Guedes et al., “Intermediate results of iStent or iStent inject implantation combined with cataract surgery in a real-world setting: a longitudinal retrospective study”, Ophthalmol Ther, 8, 87 (2019). PMID: 30721523.
J Belda et al., "Clinical And Economic Outcomes Of Microinvasive Glaucoma Surgery (MIGS) With Stents In Patients With Mild-To-Moderate Or Refractory Glaucoma In Spain", Value Heal, 20 (2017).
M Teus et al., "Análisis de impacto presupuestario de la introducción de iStent inject® para el tratamiento del glaucoma de ángulo abierto en España". Poster presented at XXXIX Jornadas de Economía de la Salud, Albacete 12-14 June 2019.
H Ziaei, L Au, "7 year results & Cost Analysis". Manchester iStent Study. Poster March 2019 WGC.
J Hooshmand et al., “Minimally invasive glaucoma surgery: comparison of iStent with iStent inject in primary open angle glaucoma”, Clin Exp
Ophthalmol, 47, 898 (2019). PMID: 31034687.