These pearls have 1st class pedigree

Need guidance on combination cataract and glaucoma surgeries? Get a string: You’ll find many pearls below.

By Karen Blum

Surgeons have long performed combined cataract and glaucoma surgeries. But in days past, it was one procedure fits all, and management of glaucoma did not differ between patients. Through advances in recent years, however, most notably the introduction of microinvasive glaucoma surgeries (MIGS), a new range of options are available to manage glaucoma, allowing doctors to better personalize treatment at different stages of the disease.

Before MIGS, “The only option we had with cataract surgery was doing a trabeculectomy, which was never that great of a procedure when done [with cataract removal], because inflammation from the cataract surgery often made the trab fail from the get-go,” says Joseph Gira, MD, an ophthalmic surgeon with Ophthalmology Consultants, Ltd., in St. Louis. “[MIGS have] really improved our ability to treat the glaucoma alongside the cataract. The iStent [Glaukos, approved in 2012] is only the start of it — there are a lot more MIGS procedures and products coming down the pipeline.”

Cataract surgery as glaucoma treatment

While surgeons have known anecdotally that removing the cataract alone could lower intraocular pressure, research like the Ocular Hypertension Treatment Study better defined the results. Cataract removal, which can achieve a 4- to 5-point drop in pressure, is now considered frontline treatment for patients with narrow angle glaucoma, says Alan Crandall, MD, clinical professor, senior vice chair of ophthalmology and visual sciences, and director of glaucoma and cataract at the University of Utah’s Moran Eye Center in Salt Lake City. Adding the iStent can take pressure down another 2 to 3 points.

“MIGS is a very promising field,” adds Dr. Crandall. “The advantage of the iStent or any of these minimally invasive procedures is you don’t have to do a lot of follow-up, patients don’t have a bleb, there’s not a risk for infection. The question is, is it also minimally effective as well as minimally invasive? There’s a lot of controversy around that — some glaucoma specialists feel it’s garbage, that if you’re only getting a 2-point drop it’s not worth the money. Others love it.

“It does give you an option to manage mild-to-moderate glaucoma without having a bleb-related surgery, which is really significant for the patient.”

Decisions, decisions

As for making a decision about what glaucoma procedure to combine with cataract, look at a patient’s target pressure and how far off from that he/she is, says Iqbal “Ike” Ahmed, MD, assistant professor, University of Toronto and chief, ophthalmology division at Trillium Health Partners in Mississauga, Ontario. If patients are at target pressure on one drop or no medication, he says, there’s no need for combined surgery; just remove the cataract. But, if patients need a pressure of 13 but are at 28 despite taking multiple medications, that person would more likely benefit from a trabeculectomy combined with cataract surgery.

The many patients in the middle — whose pressure is not ideally controlled but flirt with the target and whose glaucoma severity isn’t bad — can benefit from combining cataract surgery with MIGS, Dr. Ahmed says. It’s minimally risky while achieving the necessary drop in pressure.

“My approach is to go in a stepwise fashion, from the least invasive, safer ways to the more aggressive ways that are more potent but have a bit more risk associated with it,” Dr. Ahmed says. You can save the more aggressive surgery for later, but if there’s a good chance a less invasive procedure will work first, he does it.

Three pathways

It’s best to think about MIGS as being used in three different pathways, Dr. Ahmed says: Schlemm’s canal, the suprachoroidal space, and the subconjunctival space. Placing a microstent like the iStent (Glaukos)^* or Hydrus (Ivantis)^* in Schlemm’s canal is “ultra safe, doesn’t increase the risk of cataract and can lower the pressure beyond cataract surgery.” For the suprachoroidal space, devices like the iStent Supra^* (Glaukos) or CyPass^* (Transcend) can achieve greater pressure lowering but with a bit more risk. For the subconjunctival space, a “MIGS plus” device like the XEN gel stent^* (AqueSys) can lower pressure to a degree similar to a trabeculectomy, Dr. Ahmed says, with more risk but still with the improved safety and recovery of MIGS.

Dr. Ahmed’s team is performing fewer cataract plus trabeculectomies; leaning more toward phacoemulsification plus MIGS for those with more mild to moderate disease; or to “MIGS plus” implants with cataract surgery for those in the more significant disease category.

No cure, but many treatment choices

“It’s nice to have a spectrum for a chronic disease [that is] without a true cure,” says Robert Chang, MD, assistant professor of ophthalmology, Stanford Byers Eye Institute in Palo Alto, Calif. Besides the lone cataract surgery or cataract with MIGS, “we can do a cataract and trabeculectomy or cataract and tube shunt, which is currently our best pressure-lowering that we can achieve in a single surgery.”

Diagnostic equipment also has improved, he says, and it’s much easier with OCT to assess where the nerve fiber layer is before visual field loss and to match the appropriate minimally invasive, less risky surgery with glaucoma severity. The result is being better able to intervene earlier with safer surgical options, and to personalize medicine to each patient’s disease stage and rate of progression, given age and lifestyle instead of just relying on general target pressure ranges. In someone over 90 years old who has failed meds and SLT, he says, maybe just removing the cataract is enough without subjecting the person to a bleb surgery, even with advanced disease.

“[Managing] glaucoma still has a bit of an art to it,” Dr. Chang says. “Now we have a bigger palette of surgical options to [enhance] quality of life by maintaining vision with less risk than before. I think every glaucoma specialist should learn a TM-based procedure, a suprachoroidal-based procedure, and an aqueous reduction procedure to maximize alternate options before having to proceed to trabeculectomy or tube shunt as the full bypass surgery.”

Beyond MIGS, says Dr. Crandall, there have been multiple studies including the TVT (Tube Versus Trabeculectomy) study indicating that tube implants achieve similar results to trabs, resulting in more surgeons using Ahmed valves or Molteno valves along with cataract surgery. The combination is technically difficult, however, and there are no long-term data. Also, he says, endoscopic cyclophotocoagulation (ECP), which once was considered less effective or more inflammation-causing, is more frequently used because of the availability of better tubes and better ways of delivering the energy. Together, he says, the advances “have offered us a way of really fine-tuning treatment for each individual.”

An easy sell

Selling patients on combined surgery “is really not an issue,” Dr. Crandall says.

“It’s not difficult to convince glaucoma patients if you even have a chance of lowering their risk for blindness, followed by the risk for not being able to pay for their medications, which is really critical, followed by the high likelihood that only 20% to 30% of your patients at best are really doing what they’re supposed to do,” he says.

Dr. Gira agrees: “Most patients, when given the notion they could possibly get off drops or diminish the amount of drops they’re using, they love it.”

Insurers cover the combined surgery, with the slight downside to surgeons of only getting reimbursed half of their time for the second surgery. But, Dr. Chang says he doesn’t think surgeons make decisions based on that, “particularly because removing cataracts makes it easier to perform most glaucoma surgeries.”

In some patients, like those with mild to moderate glaucoma, there may still be arguments for doing the surgeries separately. “If you’re not a big iStent fan, then you’re well justified just to do the cataract because you can always add the trab later,” Dr. Crandall says. “Doing the trab first is much less in the thinking process because it always speeds up cataract, and then going back in increases the risk of trab failure.”

Sometimes it is better to space out surgeries if the eye is at risk for a lot of inflammation or bleeding with a combined surgery, says Dr. Chang. Also, insurance might not cover lens removal. Only certain types of glaucoma qualify for coverage for removal of a clear lens, as opposed to removal of a cataract due to a visually significant complaint, he says. “If a patient has 20/20 vision without complaint and you think removing the lens will help with pressure-lowering, it may not be covered. It is an easier decision when patients complain of a cataract and they also have glaucoma not controlled with laser or meds, because then we can take care of both at the same time.”

Still, the surgical advantage remains to do the procedures together, which frequently results in getting patients off glaucoma medications. “Even if you need to start them back on a drop in three to five years, the less medication they need, the better off they are,” Dr. Crandall says. OM

Dr. Ahmed has served as a consultant for AqueSys, Ivantis, Glaukos and Transcend Medical.
Dr. Crandall has served as a consultant for Glaukos and Ivantis. Dr. Chang has served as a consultant for Transcend Medical.

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