Interventional glaucoma is arguably the most talked about development in open-angle glaucoma treatment since the introduction of micro-invasive glaucoma surgery (MIGS) more than a decade ago. Yet some ophthalmologists may still question why, and how, they should adopt this approach. Here, Mark Gallardo, MD, and Brian Shafer, MD, discuss their experiences with implementing interventional glaucoma in their own practices—and the advantages that it has brought.
Q: Interventional glaucoma (IG) is described as a more proactive treatment paradigm than traditional approaches to managing glaucoma. Why should physicians consider switching to it?
Mark Gallardo, MD: First, IG is based on the risk of disease progression vs. progression alone. Our objective is to preserve the optic nerve structure and function, but historical training required us to confirm progressive thinning of the retinal nerve fiber layer and/or visual field loss on three consecutive visits before intervening. This defeats the purpose of our therapeutic goal. The second facet to IG is understanding that disease is not limited to the optic nerve, but also encompasses significant change to the conventional outflow system—and that topical therapy may not be the best treatment option. Multiple side effects are associated with topical therapy, including ocular surface disease, dry eye, periorbital fat atrophy, and several others that adversely affect quality of life and vision.1
Furthermore, it has been proven that benzalkonium chloride is cytotoxic to the trabecular meshwork endo-thelial cells,2 leading to a reduction in the effective filtration area. If you look at glaucoma as a disease not only of the optic nerve, but also of the conventional outflow system (exacerbated by eye drops), devices like the iStent infinite® Trabecular Micro-Bypass System (Glaukos) can be used to augment the natural outflow system. The iStent infinite is the first and only MIGS device designed and FDA-cleared for standalone treatment of patients with primary open-angle glaucoma (POAG) in whom previous medical and surgical treatment has failed.
Brian Shafer, MD: Things have also changed on the diagnostic side. When the landmark glaucoma trials took place, there was no OCT. We were following patients when they already had death of ganglion cells and loss of nerve fiber layer. We now have easier ways to do visual field tests with the Radius XR™ (Glaukos partnership), a wearable patient engagement and diagnostic system that enables us to follow visual fields much more comfortably for patients and more efficiently for our clinics.
Q: How quickly do you think IG will be broadly adopted?
Dr. Gallardo: Interventional glaucoma is in the same position that MIGS was over a decade ago. Before MIGS, surgery was limited to patients with moderate to severe glaucoma who were on maximum tolerated medical therapy (MTMT). MIGS was initially met with skepticism because the results were not as efficacious compared to trabeculectomy. With time, MIGS prompted us to view surgery as a means to not only reducing IOP, but also to reducing medication burden, and delaying the need for more invasive procedures. This brought about a huge paradigm shift—we began to treat the complete eye system, as opposed to individual disease. Now we’re again rethinking the treatment paradigm, and it’s going to take some time to adopt this new approach, just as it did with MIGS.
Dr. Shafer: Before a patient’s first appointment, they receive customized videos introducing the entire spectrum of glaucoma therapy, so they arrive primed to hear about the various interventions that I may prescribe. Next, they get a fundus photo, an OCT of the nerve fiber layers and ganglion cells, pachymetry, and a Radius XR virtual field test. By the time I walk into the room, I have their entire glaucoma portfolio in front of me.
Typically, my first recommendation for treatment is to do a selective laser trabeculoplasty (SLT) or to implant a procedural pharmaceutical device like iDose® TR (travoprost intracameral implant) 75 mcg (Glaukos). The key is leading with the procedure, rather than tiptoeing into it. Nine times out of 10, the patient follows my recommendation.
Dr. Gallardo: I agree. If I’m talking about a trabecul-ectomy, I’m talking about wound leaks, hypotony, choroid diffusions, suprachoroidal hemorrhages, and fluorouracil (5FU) injections. That scares patients. But when I discuss the safety, efficiency, risks, and limited recovery times of SLT, procedures like iDose® TR 75 mcg, or MIGS procedures, they’re very eager to move forward.
Q: What are some of the challenges you face with IG, and how do you overcome them?
Dr. Gallardo: The big gorilla limiting my ideal therapeutic algorithm is insurance coverage. The reality is insurance companies have become very involved in stipulating what procedures can and cannot be performed. Insurance companies may require the patient meets certain criteria that may not perfectly align with the label for the device.
Dr. Shafer: I work at a physician-owned, ophthalmology-specific ambulatory surgical center (ASC) 20 minutes from my clinic. Despite the clinical requirements and associated logistics for a patient to have a procedure in the ASC, most patients still opt for this interventional approach because everyone involved appreciates the benefits of early procedural intervention.
Other interventional modalities, such as SLT and pro-cedural pharmaceuticals, can be done in the clinic. For example, a permanent J code for iDose TR went into effect on July 1, 2024. We expect the reimbursement process to be
far more streamlined going forward.
Q: In the meantime, what can alleviate these issues?
Dr. Shafer: What could be extraordinarily helpful in the glaucoma space is what Glaukos does for crosslinking in the cornea space. The company created Glaukos Patient Services (GPS), which runs the patient’s insurance eligibility and obtains prior authorization. That would be a huge game-changer in the glaucoma space.
Q: What will it take for IG to gain wider acceptance?
Dr. Gallardo: It’s going to take a critical mass of thought leaders demonstrating their own application of interventional glaucoma and discussing the benefits to get other providers on board. Fortunately, we already have a significant library of data proving the safety and efficacy of laser therapy, procedural pharmaceuticals, and a multitude of MIGS procedures.
The LiGHT trial3 propelled us to rethink how we manage newly diagnosed glaucoma, because it found the benefits of SLT outweigh those of drops as first-line therapy. Similarly, a recent meta-analysis by Gillmann5 found that iStent® technologies preserved visual field.
Dr. Shafer: I know retina colleagues who remember going from no therapies for retinal disease to laser, and then to intravitreal injections. As that paradigm shift was happening, there were people saying, “You’re going to stick a needle in their eye?” Now, injections are a staple of retina practices. That change is due to the DRCR Network pulling together treatment protocols for various retinal diseases. Similar protocols for glaucoma would provide a framework for doctors who don’t know how to enter the IG space.
REFERENCES
1. Baudouin C. Detrimental effect of preservatives in eyedrops: implications for the treatment of glaucoma. Acta Ophthalmol. 2008;86(7):716-726.
2. Seino S, Takada Y, Saika S. [Effects of Benzalkonium Chloride in Ophthalmic Eyedrop Medications on Corneal Epithelium]. Yakugaku Zasshi. 2021;141(1):35-39.
3. Gazzard G, Konstantakopoulou E, Garway-Heath D, et al. Laser in glaucoma and ocular hypertension (LiGHT) trial: Six-year results of primary selective laser trabeculoplasty versus eye drops for the treatment of glaucoma and ocular hypertension. Ophthalmology. 2023;130(2):139-151.
4. Holmes DP, Clement CI, Nguyen V, et al. Comparative study of 2-year outcomes for Hydrus or iStent inject microinvasive glaucoma surgery implants with cataract surgery. Clin Exper Ophthalmol. 2022: 50(3):263.
5. Gillmann K, Hornbeak DM. Rates of visual field change and functional progression in glaucoma following trabecular microbypass implantation of iStent technologies: a meta-analysis. BMJ Open Ophthalmol. 2024 Feb 15;9(1):e001575.
IMPORTANT SAFETY INFORMATION:
iSTENT INFINITE® INDICATIONS FOR USE. The iStent infinite® Trabecular Micro-Bypass System Model iS3 is an implantable device intended to reduce the intraocular pressure (IOP) of the eye. It is indicated for use in adult patients with primary open-angle glaucoma in whom previous medical and surgical treatment has failed. CONTRAINDICATIONS. The iStent infinite is contraindicated in eyes with angle-closure glaucoma where the angle has not been surgically opened, acute traumatic, malignant, active uveitic, or active neovascular glaucoma, discernible congenital anomalies of the anterior chamber (AC) angle, retrobulbar tumor, thyroid eye disease, or Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure. WARNINGS. Gonioscopy should be performed prior to surgery to exclude congenital anomalies of the angle, PAS, rubeosis, or conditions that would prohibit adequate visualization that could lead to improper placement of the stent and pose a hazard. MRI INFORMATION. The iStent infinite is MRConditional, i.e., the device is safe for use in a specified MR environment under specified conditions; please see Directions for Use (DFU) label for details. PRECAUTIONS. The surgeon should monitor the patient postoperatively for proper maintenance of IOP. Three out of 61 participants (4.9%) in the pivotal clinical trial were phakic. Therefore, there is insufficient evidence to determine whether the clinical performance of the device may be different in those who are phakic versus in those who are pseudophakic. ADVERSE EVENTS. The most common postoperative adverse events reported in the iStent infinite pivotal trial included IOP increase ≥ 10 mmHg vs. baseline IOP (8.2%), loss of BSCVA ≥ 2 lines (11.5%), ocular surface disease (11.5%), perioperative inflammation (6.6%) and visual field loss ≥ 2.5 dB (6.6%). CAUTION: Federal law restricts this device to sale by, or on the order of, a physician. Please see DFU for a complete list of contraindications, warnings, precautions, and adverse events.
iDOSE® TR INDICATIONS AND USAGE. iDose TR (travoprost intracameral implant) is indicated for the reduction of intraocular pressure (IOP) in patients with open angle glaucoma (OAG) or ocular hypertension (OHT). DOSAGE AND ADMINISTRATION. For ophthalmic intracameral administration. The intracameral administration should be carried out under standard aseptic conditions. CONTRAINDICATIONS. iDose TR is contraindicated in patients with active or suspected ocular or periocular infections, patients with corneal endothelial cell dystrophy (e.g., Fuch’s Dystrophy, corneal guttatae), patients with prior corneal transplantation, or endothelial cell transplants (e.g., Descemet’s Stripping Automated Endothelial Keratoplasty [DSAEK]), patients with hypersensitivity to travoprost or to any other components of the product. WARNINGS AND PRECAUTIONS. iDose TR should be used with caution in patients with narrow angles or other angle abnormalities. Monitor patients routinely to confirm the location of the iDose TR at the site of administration. Increased pigmentation of the iris can occur. Iris pigmentation is likely to be permanent. ADVERSE REACTIONS. In controlled studies, the most common ocular adverse reactions reported in 2% to 6% of patients were increases in intraocular pressure, iritis, dry eye, visual field defects, eye pain, ocular hyperaemia, and reduced visual acuity. PLEASE SEE FULL PRESCRIBING INFORMATION at www.glaukos.com/wp-content/uploads/2024/03/iDose-TR-Prescribing-Information.pdf. You are encouraged to report all side effects to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088. You may also call Glaukos at 1-888-404-1644.
RADIUS XR™ INDICATIONS FOR USE: Radius is an automated perimeter intended to identify visual field defects for screening, monitoring, and assisting in diagnosing and managing ocular diseases such as glaucoma. Radius is not intended to be the sole diagnostic method for ocular diseases. Instead, it complements other diagnostic tools and clinical evaluation of the patient’s visual field.
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