Currently, glaucoma better managed with surgery
The first minimally invasive or microinvasive glaucoma surgery to consider when treating a patient with open-angle glaucoma is selective laser trabeculoplasty. We did a recent cover story on SLT, and well-performed studies confirm that SLT is an underutilized minimally invasive procedure to treat open-angle glaucoma with good efficacy and rare postoperative complications. It is definitely easy on patients to have SLT performed in the office, ASC or hospital outpatient department, and reimbursement is reasonable and reliable. SLT is an accepted procedure worldwide and effective in all races. A next-generation SLT is under development by Belkin Laser of Israel and promises to make this procedure quicker and easier to perform. So, my first thought is that many of us should be offering SLT to more of our patients, especially those who require more than two drops a day, at which compliance falls dramatically.
Other laser procedures such as laser peripheral iridotomy, whichever laser is used, also fit in the category of MIGS, in my opinion. The various forms of cyclophotocoagulation, including Iridex MicroPulse, while valuable tools in our practice, are somewhat more invasive and reserved mainly for patients who are unable to undergo other procedures or are unresponsive to them.
The second best MIGS procedure for me is lens removal by phacoemulsification, usually combined with IOL placement. It is the phacoemulsification that positively affects the patient’s IOP, not the IOL, but the two are usually done simultaneously for optical reasons. Phacoemulsification is beneficial whether the patient has narrow-angle, open-angle or combined-mechanism glaucoma. Even better, the pressure lowering after phacoemulsification is proportional to the preoperative IOP. Patients who present with higher preoperative IOPs usually achieve a greater pressure-lowering benefit. Open-angle glaucoma patients with a washout pressure of 25 mm Hg to 28 mm Hg can expect their IOP to be reduced 6 mm Hg to 8 mm Hg. Those with preoperative IOPs higher than 30 mm Hg often achieve an 8 mm Hg to 10 mm Hg drop in IOP.
Phacoemulsification alone is an amazing glaucoma procedure. In the years after phacoemulsification surgery, the IOP may drift slightly higher, but the beneficial effect of lens removal is quite durable, and in studies at Minnesota Eye Consultants, we found good efficacy for more than 10 years postoperatively. Fortunately, the IOP reduction occurs after the removal of clear or cataractous natural lenses. In patients with angle closure, the best treatment is usually phacoemulsification of the clear natural lens. Peripheral synechiolysis, according to recent studies, adds no value and is not necessary. The positive impact of phacoemulsification on IOP leads me to offer cataract surgery at an earlier stage to patients with glaucoma, and many surgeons agree.
Today, while in the operating room performing phacoemulsification and IOL placement, we now have the opportunity to perform one of several MIGS procedures discussed in the accompanying cover story. In my practice, if the patient requires topical medications to treat their IOP, I always offer them the opportunity to have MIGS performed at the same time as their cataract surgery. This, in my opinion, is the current standard of care. My favorite intraocular MIGS is a trabecular bypass procedure, but there are many excellent choices. The addition of MIGS to cataract surgery at a minimum is capable of reducing postoperative medication burden and in most patients results in an incremental reduction in IOP over that achieved with lens removal alone. MIGS is also compatible with refractive cataract surgery.
We all have a different definition of which procedures we include in MIGS and which we do not. For me, if a bleb is created that can induce hypotony or require postoperative needling procedures, I place it in the category of minimally invasive or microinvasive filtration surgery, or MIFS, and that is a separate category requiring more skill in postoperative management. Many ophthalmologists without glaucoma fellowship training or a special interest in glaucoma do not enjoy managing filtering blebs for a patient’s lifetime, making MIFS most popular with the glaucoma specialist.
Every year, glaucoma is transitioning more to a disease category better managed with surgery than topical or oral antihypertensive medications. The development of extended-release medications delivered by punctal plugs, conjunctival explants or intracameral injections may reverse this trend, but for now we can expect an increasing volume of laser, ab interno and ab externo MIGS procedures to be performed every year. Besides focusing on our office practices and increasing patient throughput, the addition of a MIGS procedure to the 15% to 20% of patients with glaucoma who present for cataract surgery can significantly benefit patients and go a long way toward mitigating our current financial challenges.
- Gazzard G, et al. Lancet. 2019;doi:10.1016/S0140-6736(18)32213-X.
Disclosure: Lindstrom reports relevant financial disclosures for AqueSys, Allergan, Alcon, Bausch Health, Belkin Laser, Glaukos, Johnson & Johnson Vision, Transcend and Zeiss.