In this video from Interventional Mindset, Drs. Nathan Radcliffe and David Goldman discuss a cataract and refractive surgeon's perspective on adopting minimally invasive glaucoma surgery (MIGS).
A primary goal of all physicians is to consistently enhance patient care by making necessary procedures more accessible, well-tolerated, and quicker to potentially achieve the desired outcomes.
Adding MIGS to his surgical services has empowered Dr. Goldman—a refractive and cataract specialist—to better serve the large patient population who contend with both cataracts and glaucoma.
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Browse through our videos on a variety of topics within cataract and refractive surgery, glaucoma, and ocular surface disease to learn practical insights into adopting a variety of new surgical techniques and technology.
A matter of supply and demand
Though his focus was on corneal disease and premium cataract implants, Dr. Goldman realized he was seeing an influx of glaucoma patients on a more frequent basis. This, coupled with the fact that many of the glaucoma specialists in his area were already inundated with patients (making referral difficult), caused Dr. Goldman to reevaluate his protocol and incorporate MIGS for suitable patients that might benefit from receiving an intraocular pressure (IOP) lowering procedure alongside their cataract surgery.
“The first obstacle to overcome was the academic mindset that specialists must strictly stick to their specialty.”
There was also a level of concern about the possibility of offending surrounding glaucoma specialists. Dr. Goldman found that when their colleagues are working within the accepted parameters, most glaucoma and cataract/refractive specialists (comprehensive ophthalmologists and the other various subspecialists, too) are grateful to call themselves allies committed to making sure patients are treated in the most timely and efficient manner.
MIGS: past and present
To date, Dr. Goldman has performed a wide array of MIGS procedures in conjunction with IOL implants and occasionally as a standalone operation in pseudophakic patients primarily.
Previously and presently used MIGS include:
- iStent inject W and iStent infinite (Glaukos): These heparin-coated, non-ferromagnetic titanium stents create pathways through the trabecular meshwork (TM) and have been specifically designed to be implanted during cataract surgery or as standalone, depending on case presentation.1
- Endoscopic Cyclophotocoagulation (ECP): Noted for a high safety profile, ECP lowers IOP via the reduction of aqueous humor production with transscleral ciliary body ablation.2
- KDB GLIDE (New World Medical): With its sharp, tapered tip, this next-generation device (original Kahook Dual Blade) has the capacity to remove the trabecular meshwork nearly completely through parallel goniotomy.1 Additional features of this device include enhanced dual blades with a rounded heel, tapered sides, and a smaller footplate to incise and remove the TM.
- Hydrus microstent (Alcon): Made of nitinol, a highly flexible and biocompatible material, the eyelash-sized Hydrus bypasses the trabecular meshwork and is implanted in the Schlemm’s canal where its scaffold design allows it to span approximately 90° of the canal.
- OMNI Surgical System: Indicated for patients with primary open-angle glaucoma, OMNI allows surgeons to perform canaloplasty followed by trabeculotomy using a single device.
- XEN Gel Stent: Using an ab interno approach, this 6mm hydrophilic tube is placed in the subconjunctival space to lower IOP and is indicated for refractory glaucoma patients.4
- *CyPass (Alcon): After the device was linked to increased endothelial cell loss (ECL), Alcon initiated a voluntary market withdrawal of the microstent in August 2018.3
Though not specifically mentioned in this video, STREAMLINE Surgical System (New World Medical) represents another available MIGS option. This device creates a micro-goniotomy in the TM and then delivers viscoelastic into Schlemm’s canal to dilate the canal and collector channels. Surgeons can create multiple goniotomies over a range of clock hours.
While each MIGS device has pros and cons, the vast majority do not significantly increase the inherent surgical risk but can offer a significant benefit. Also, as with all procedures, confidence and proper surgical technique improve MIGS success rates, so while a fellowship is perhaps not necessary, training and practice are.
The benefits of XEN Gel Stent
Initially, like many surgeons, Dr. Goldman was a bit leary of the ab interno bleb created during XEN Gel Stent implantation, as this typically escalates the risk for bleb fibrosis. However, he was eager to gain a similar IOP-lowering effect found with CyPass prior to its recall and saw the possibilities with XEN. After undergoing training, Dr. Goldman realized the learning curve was much less steep than he originally thought. And XEN Gel Stent has not disappointed—many of his patients find their IOPs leveling out in the low teens and are able to reduce or eliminate glaucoma drops.
Though XEN Gel Stent normally does not require any additional modifications afterward, occasionally, there is the need for bleb needling. To prepare patients for glaucoma surgery, Dr. Goldman introduces XEN as a two-part procedure: stent implantation and then follow-up revision to achieve the target IOP. Further, if fibrosis is evident at the 3- to 5-week mark—which occurs in approximately one out of three patients—the additional procedure is viewed as an expectation, not a complication.
Do MIGS impact premium intraocular lens outcomes?
There is a belief in the ophthalmic community that MIGS might have a negative effect on cataract surgeries involving premium intraocular lenses (IOLs). In Dr. Goldman’s professional opinion, this label is a misconception of sorts.
With proper patient selection and today’s improved premium IOL technologies, he finds recovery rate and visual results to be comparable to premium patients who did not undergo MIGS. He credits some of this to developing an algorithm that helps him determine which patient would have a higher likelihood of benefiting from MIGS procedure.
The effect of MIGS on ocular surface health
Oftentimes, cataract surgery can exacerbate underlying ocular surface disease, inclusive of dry eye and blepharitis. Additionally, the chronic use of glaucoma drops is notorious for causing ocular surface and meibomian gland damage which has led both physicians to believe MIGS can go a long way toward mitigating the burden on the ocular surface.
By lowering IOP through surgery and reducing the quantity of drops, especially those containing benzalkonium chloride (BAK), patients can begin to potentially gain a healthier ocular surface. Subsequently, improved stability within the tear film can lead to a higher quality vision as well as enhanced comfort in daily quality of life and work-based activities.
Post-operative patient satisfaction
Though Dr. Goldman has seen incredible patient satisfaction after a refractive procedure, it pales in comparison to the relief glaucoma patients feel when they are able to live the drop-free life that can come from a MIGS procedure. If, in addition, the patient ends up being spectacle-free, satisfaction is almost guaranteed.
“However, Dr. Goldman adheres to the philosophy of ‘under promise and over deliver.’”
He does not ensure the patient will walk away drop-free after surgery; instead, he explains that, at the very least, MIGS will lower their IOP and potentially allow for more control of their glaucoma. He has discovered that most patients are equally interested in lowering their pressure and improving their vision and are, therefore, eager to include MIGS as a treatment option in their decision-making, especially upon finding it is usually covered by insurance.
In conclusion
With more patients longing to be both spectacle and drop-free, Dr. Goldman sees a movement toward glaucoma being treated more as a surgical disease as opposed to a pharmacological disease.
As many of these patients suffer from not only cataracts and glaucoma but associated ocular surface disease, it is only logical to take a more holistic approach and employ all the tools and technologies available to yield optimal results. Dr. Goldman has found his patients are better served and satisfied since he adopted this approach and incorporated MIGS into his practice.
