October 2017

COVER FEATURE

Challenging cataract cases
Managing cataract with advanced glaucoma


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer

John Odette, MD, discusses insertion of one of his first CyPass stents.



Combining MIGS procedures can improve their efficacy while maintaining the safety profile. One such combination begins with the implantation of a CyPass Micro-Stent.

After CyPass implantation, a left-going iStent is implanted in an area of Schlemm’s canal thought to be occupied by scleral collector channels identified beforehand by finding the location of aqueous veins in the conjunctiva.


Finally, a right-going iStent is implanted in a similar targeted fashion to maximize trabecular outflow. After completion, two well-placed iStents can be seen with appropriate reflux bleeding from Schlemm’s canal on either side of the central CyPass implant.
Source (all): Won Kim, MD



 

Devising a treatment strategy to lower IOP in glaucoma that has progressed to moderate and advanced stages in eyes with cataract now includes MIGS as a standard option

Patients on maximal medical glaucoma therapy need new solutions. Drop regimens are tedious, with efficacy only as good as the patient’s adherence to the drop protocol and their pressure-lowering effect in hard cases dwindling. When cataract enters the picture, clinicians are in a favorable position to maximize IOP reduction by implanting microinvasive glaucoma surgery (MIGS) devices or performing trabeculectomy, if needed. Attitudes on trabeculectomy as the gold standard treatment for advanced glaucoma cases are divided, owing to the relative surgical simplicity and high efficacy of different MIGS implants.

Yes to MIGS with cataract

According to Won Kim, MD, Walter Reed National Military Medical Center, Bethesda, Maryland, MIGS has an important role in cataract cases with advanced glaucoma. “This idea that MIGS procedures are somehow off limits for patients with advanced glaucoma is misguided,” Dr. Kim said. “Before the advent of MIGS procedures, many glaucoma surgeons often did cataract surgery alone in the setting of patients with advanced glaucoma who were well controlled on multiple medications. Why? Because we knew adding a trabeculectomy or glaucoma drainage implant to the cataract surgery in this setting would greatly elevate the risk for complications and delay the visual recovery. We would also reason to ourselves that cataract surgery itself has a small chance of modest pressure lowering and thus we could help with glaucoma control without a trab or tube. Then, if we desired further IOP lowering or greater medication burden reduction, we could do a trabeculectomy or drainage implant as a separate procedure months later. Taking this mentality, why wouldn’t you consider doing MIGS with cataract surgery in this setting? You will give patients a procedure that is comparable to cataract surgery alone in terms of safety and rapid visual recovery while giving them a much better chance at lowering IOP and/or medication burden. You can always go back and do the more aggressive traditional glaucoma filtration surgeries later if you need to. In my experience, that will only very rarely be the case.”
Dr. Kim will typically combine glaucoma procedures in patients with more advanced disease, especially when seeking to avoid traditional filtration surgery in patients at a high risk for complications, such as high myopes and those who are post-vitrectomy or post-scleral buckle. He prefers to avoid traditional filtration surgery in monocular and young patients as well because they would have to live many decades with the lifelong risks of bleb-related infections and tube-related complications. “I have used the Trabectome [NeoMedix, Tustin, California] and endoscopic cyclophotocoagulation (ECP) combination in post-vitrectomy and scleral buckle patients because of the high risk for trab failure and the increased risk for complications such as tube erosion after tube shunts. I have used that combination for patients with very thin sclera such as osteogenesis imperfecta and scleritis where their sclera likely would not have allowed for a trab or tube. For patients with advanced disease who have already failed consecutively both trab and tube, I have often performed the gonioscopy-assisted transluminal trabeculotomy (GATT) and 360-degree ECP combination. In monocular patients with advanced disease where I want to minimize the risk for hyphema but I want greater IOP lowering than what a typical MIGS procedure might provide, I have combined limited ab interno trabeculectomy, performed with the Trabectome or Kahook Dual Blade [New World Medical, Rancho Cucamonga, California], with ab interno canaloplasty and ECP. More recently I have been utilizing the CyPass Micro-Stent [Alcon, Fort Worth, Texas] combined with multiple targeted iStent [Glaukos, San Clemente, California] placement. All of these combinations can work very well and not uncommonly will produce IOP in the low teens with a reduction in medication burden,” Dr. Kim said. 

Yes to iStent for moderate glaucoma

Yuri McKee, MD, Mesa, Arizona, agrees that the more help you have in lowering IOP, the better. However, to avoid reimbursement issues, Dr. McKee sticks to the iStent, which is indicated for implantation at the time of cataract surgery. “I use the iStent in patients with mild, moderate, or advanced glaucoma because the higher the pressure, the better the effect of the iStent. In these cases, every little bit helps. I do not think the iStent is the last thing that will be required in cases of advanced glaucoma, as its indication is for mild to moderate disease, but it still is useful in advanced glaucoma because it is going to give you some pressure reduction, and every little bit counts,” Dr. McKee said.
The iStent is most effective in patients with still viable drainage systems. Advanced glaucoma, however, is often associated with pathology of the trabecular meshwork, blocking egress of aqueous humor through the conventional pathway. The uveoscleral pathway and suprachoroidal space therefore represent important outflow alternatives. Despite the large absorptive capacity of the supraciliary space, Dr. McKee thinks that it may be best to avoid stenting to the suprachoroidal/supraciliary spaces. “My issue with suprachoroidal MIGS is that there is a concerning rate of CME associated with these devices. If you think about it, you are connecting the anterior chamber directly to the suprachoroidal space, so any inflammation in the anterior chamber is going to have a direct passageway to the subfoveal space and can cause CME. Currently, I am not doing any suprachoroidal MIGS procedures. I prefer to stick to the iStent and the Xen Gel Stent [Allergan, Dublin, Ireland]. I prefer to do the Xen as a standalone procedure,” he said. The Xen is approved for patients with refractory glaucoma who failed previous surgical treatments or in patients with open angle glaucoma, pseudoexfoliative or pigmentary glaucoma with open angles who are unresponsive to maximum tolerated medical therapy.

Yes to Xen for advanced glaucoma

“Xen diverts fluids to the subconjunctival space, and I have found that to be extremely effective in cases of advanced glaucoma,” Dr. McKee said. “The iStent gives somewhat less pressure reduction. My experience with the iStent, of which I have done approximately 455 in the last 24 months, is a two-point reduction when combined with cataract surgery. For mild to moderate glaucoma, where you want a pressure of 14 mm Hg or less, with the patient’s IOP between 15 and 17 mm Hg, you can combine the iStent with cataract surgery. But if you need a pressure reduction of 8–10 mm Hg in advanced or refractory glaucoma, the Xen is going to get you there 80% of the time straight out of the gate. In the other 20% of the time, you will need a little extra maneuvering, like drops or bleb needling.”
Dr. Kim has a similar mindset that trab and tubes have been largely replaced by the Xen. “Tube and trab in the setting of cataract and glaucoma, for me, are only applicable in those cases with severe field loss and IOP out of control on maximum medical therapy. With the advent of the Xen, if patients have healthy conjunctiva, I will almost always choose this over trab or tube. This is because the Xen offers a more controlled and predictable postop course, with less chance for hypotony. There will be no risk for diplopia, tube erosion, or wound leaks. It doesn’t violate anatomy as much, will be more astigmatically neutral, and allows for more rapid visual recovery, making it a better partner for cataract surgery. In this setting, I would only choose a trab if the conjunctiva is healthy and I needed very low single digit IOP, perhaps in the setting of an NTG patient showing progression with relatively low IOP. I would only choose a tube in this setting if the conjunctiva was compromised,” Dr. Kim said.
Dr. McKee implements the following measures in his advanced glaucoma patients needing cataract surgery. “First I’d do the cataract surgery with an iStent. I’d continue the topical drops and let them heal. Occasionally it is enough, but most of the times it is not—but it does get you to a better place. From here I will do a Xen implantation. I used to do trabeculectomy and tubes, however, the results with the Xen were so impressive and reliable, the safety margin was better, and the surgery was easier on both the doctor and patient in terms of it being minimally invasive that I only offer the Xen at this point. I do not see why I should do a trabeculectomy when I can get better results with the Xen in a minimally invasive manner, which is much less stressful on the patient,” he said.

Yes to CyPass for advanced glaucoma

The more avenues eye doctors have to lower the IOP in patients who are already on max medical therapy, the better. John Odette, MD, Austin, Texas, said that MIGS devices have been a great addition to the physician’s surgical armamentarium. He thinks, however, that trabeculectomy and tubes will continue to play a significant role in glaucoma treatment for use in patients with refractory IOP elevations, despite the encouraging results obtained using MIGS devices to lower IOP. “I currently use both the iStent and the CyPass. Since it was approved for use earlier, I have placed more iStent devices, but I am finding the CyPass device to have more IOP-lowering effect than using one iStent. The Xen will hopefully help decrease many of the complications from bleb-related surgery,” he said.  
The CyPass redirects aqueous flow to the suprachoroidal space and therefore has a large capacity to significantly reduce IOP. The device is FDA approved for implantation in the eye at the time of cataract surgery.
Dr. Odette prefers not to combine glaucoma procedures, electing to perform them one at a time. “Thus far I typically do not perform more than one glaucoma procedure at a time, with the exception of cataract removal and MIGS. Since many of our glaucoma procedures are unpredictable depending on the patient, I prefer to determine the effect of one procedure prior to doing a second,” he said.
While the iStent, CyPass, and Xen are FDA approved, reimbursement is challenging for all three. Dr. McKee explained that the iStent received reimbursement but that the Medicare carrier in his area just reduced reimbursement to $200 per stent, which is untenable. The Xen is currently a cash pay procedure. He said that although patients pay cash, lifting the irritating burden of drops associated with advanced glaucoma has left them satisfied. Dr. Odette corroborated the current reimbursement challenges for almost all glaucoma and MIGS procedures, which is even harder when trying to combine procedures. “In our practice we will resort to a private pay model when necessary. However, many of the patients who have the most need for these procedures are those who can least afford a self-pay model,” Dr. Odette said.

Editors’ note: Dr. McKee has financial interests with Allergan. Drs. Kim and Odette have no financial interests related to their comments.

Contact information

Kim
: wonkim74@hotmail.com
McKee: mckeeonline@mac.com
Odette: jodette@austineye.com

Managing cataract with advanced glaucoma Managing cataract with advanced glaucoma
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