For thousands of ophthalmologists who have worked through the challenges of managing glaucoma long-term, this is a very exciting time. We are finally seeing years of research produce safer and more effective treatments. Several minimally invasive glaucoma surgery (MIGS) procedures have been approved throughout the last few years, creating headlines at national and international meetings and changing the treatment algorithm for glaucoma.

MIGS represent a paradigm shift from medical to surgical management of glaucoma. With less invasive, lower-risk surgeries, we can intervene surgically earlier than ever before in the disease process. We have options. One of these options is the CyPass Micro-Stent, which was developed by Transcend Medical and acquired by Alcon in February 2016.

The device received FDA approval in July 2016 for use in conjunction with cataract surgery for the reduction of IOP in adult patients with mild to moderate primary open-angle glaucoma (POAG). CyPass helps us address both conditions at once, simultaneously delivering clearer vision, lower IOP, and greater freedom from medications.

TREATING CATARACT AND GLAUCOMA

Nearly 1 in 5 cataract surgery patients also suffers from glaucoma.¹ For many patients, cataract surgery alone significantly lowers IOP.² We also have known that more significant long-term IOP reduction is possible when cataract surgery is combined with endoscopic cyclophotocoagulation or trabecular micro bypass.^3,4 Now we have a new, safer way to create a synergistic effect between cataract surgery and MIGS devices. The concurrent procedures also make good common sense. These patients already need surgery for visually significant cataracts, so once they have had a full surgical workup, gotten a ride to our ASC, and are prepped in the OR, it makes sense to treat both problems at once instead of bringing them in again.

COMPASS TRIAL

I participated in the pivotal COMPASS trial for FDA approval of CyPass. The trial compared cataract surgery alone versus surgery with placement of the CyPass Micro-Stent. COMPASS was a 24-site multicenter interventional randomized clinical trial designed to assess the 2-year safety and efficacy of CyPass for patients with mild to moderate POAG having phacoemulsification cataract surgery.⁴ Of 505 subjects, 374 received the CyPass Micro-Stent. Patients had similar baseline medication use and IOPs (pre-op IOP of 21 to 33 mmHg). CyPass demonstrated a significant reduction in pressure well beyond that achieved by cataract surgery. At 24 months, 77% of CyPass patients had ≥20% reduction in IOP, compared with 60% of controls. The mean decrease in IOP for CyPass was 7.4 mmHg versus 5.4 mmHg for controls (P < 0.001). Remarkably, 24 months after surgery, 85% of CyPass patients needed no IOP-lowering medications.

CyPass effectively lowered pressure without making any significant change to the risk of cataract surgery. That means we are moving closer to a more ideal pressure-lowering cataract surgery without collateral damage, which is very exciting to me.

THE CYPASS PROCEDURE

I was the second surgeon in the U.S. to implant the CyPass after FDA approval. Now, I've done more than 100 stents, and I feel very comfortable with the procedure. The learning process is simpler than some other devices, but it takes practice to position CyPass correctly. I recommend starting with patients under retrobulbar block as you gain confidence to ensure the patient will not move during surgery.

We place the CyPass Micro-Stent in the supraciliary space between the sclera and the ciliary body after the cataract procedure, using the same phaco incision. The CyPass in the CyPass applier is inserted through the incision. I use pupil-constricting medications, if needed, and viscoelastic, as well as a surgical gonioprism, to better visualize the anterior chamber angle.

Positioning the CyPass applier at the right location, posterior to the scleral spur above the iris root, I move it into the supraciliary space, place the CyPass, and retract the CyPass applier.

CONTINUED PROGRESS

On a 2015 ASCRS Foundation-sponsored trip to the Sinskey Eye Institute in Ethiopia, my colleagues and I taught Ethiopian surgeons to implant CyPass alone, without cataract surgery. The short learning curve was impressive. Although CyPass was FDA approved to be combined with cataract surgery, I think we will eventually use it as a stand-alone procedure to increase options for candidates without cataracts. CyPass would be very helpful for patients with open-angle glaucoma who have already had cataract surgery, for example, or after any canal-based surgery, trabeculectomy, or tube shunt. We need ongoing studies to make this happen. I think we will also see future research to concurrently get medication or even viscoelastic into the supraciliary space to help lower pressure even more. Certainly, the sustained release models for medication delivery coming down the pipeline offer another intriguing potential combination for MIGS and cataract surgery.

If we could treat the cataract, implant a MIGS device, and use a sustained-release medication at the same time, we could perhaps increase our ability to reduce pressures into the low teens without trabeculectomy. Any ability to combine procedures would help us reach a range of individualized target pressures. It is very exciting to have all these options for treating glaucoma. We are just now seeing the possibilities of MIGS devices and other advances, and the results are very promising. GP

References

1. Tseng VL, Yu F, Lum F, Coleman AL. Risk of fractures following cataract surgery in Medicare beneficiaries. JAMA. 2012;308(5):493-501.
2. Mansberger SL, Gordon MO, Jampel H, et al. Reduction in intraocular pressure after cataract extraction: the Ocular Hypertension Treatment Study. Ophthalmology. 2012;119(9):1826-1831.
3. Berke SJ, Cohen AJ, Sturm RT, Caronia RM, Nelson DB. Endoscopic cyclophotocoagulation (ECP) and phacoemulsification in the treatment of medically controlled primary open-angle glaucoma: poster 32. J Glaucoma. 2000;9(1):129.
4. Vold S, Ahmed II, Craven ER, et al; CyPass Study Group. Two-year COMPASS trial results: Supraciliary microstenting with phacoemulsification in patients with open-angle glaucoma and cataracts. Ophthalmology. 2016;123(10):2103-2112.

Dr. Sarkisian is Clinical Professor and Glaucoma Fellowship Director at Dean McGee Eye Institute, University of Oklahoma, Oklahoma City. He has participated in several pivotal FDA trials involving MIGS devices, and recently published a new book, Minimally Invasive Glaucoma Surgery: A Practical Guide.