Eyeworld

e news magazine of the American Society of Cataract & Refractive Surgery digital.eyeworld.org Supplement to EyeWorld July 2017 by Nathan Radcliffe, MD Unlocking the potential of the supraciliary space O ver the past 4 years or so, many cata- ract surgeons have become familiar with the ab interno approach to minimally invasive glauco- ma surgery (MIGS). For many of us, this has been achieved by implanting trabecular microbypass stents. In the more recent years, we have had alternative approaches to addressing glaucoma through the angle, such as ab interno goniotomy and ab interno viscocanalostomy. As a result, we are becoming familiar and comfortable with the algo- rithm of treating glaucoma in the angle at the time of cataract surgery. The ciliary body represents a large, easily visualized, and easily treatable target that can be comfortably approached using intraoper- ative gonioscopy at the time of cataract surgery. Unlike the trabecular meshwork, which varies in pigmen- tation, appearance, and microanatomy, the ciliary body can be reliably found at the iris root. The CyPass Micro-Stent is placed into the supraciliary space under gonioscopic visualization after cataract extraction and intraocular lens implanta- tion. My experience has been that the ciliary body is the easiest landmark to identify gonioscopically, and the tis- sue has also been the most intuitive target to hit with the supraciliary stent. When we target the trabecular meshwork, we know there is a floor in terms of how low we can get the intraocular pressure because we will have additional resistance to the remainder of Schlemm's canal, the collector chan- nels, and the episcleral ve- nous system. Episcleral ve- nous pressures can typically be around 12 mm Hg, so with the added resistance, trabecular bypass can often result in pressures higher than that. The ciliary space presents a unique opportunity to achieve significant pressure reduction in a safe and minimally invasive manner. The design of the CyPass Micro-Stent provides a level of resistance to aqueous outflow, and the supracili- ary space provides access to the uveoscleral outflow pathway, whereby the intra- ocular pressure will not be limited by episcleral venous pressure. Significant pres- sure reduction can occur, and, because the tip of the CyPass Micro-Stent remains in the angle and free of ob- struction, iris adhesions and other forms of scar forma- tion are less likely to influ- ence pressure reduction. Because we are accessing a space with so much pres- sure-lowering potential and using a microstent that is designed to protect against clinically significant hypot- ony, we are maximizing the potential of the supraciliary space without compromis- ing on safety as compared to cataract surgery alone. Therefore, it makes so much sense to approach the supraciliary space using a MIGS implant—so that we can control the flow. Glaucoma is a progressive and blinding disease, and medications themselves carry risk of ocular surface disease and are often diffi- cult for patients to comply with. We cannot call topical therapy risk-free. Cataract surgery provides us the opportunity to lower the pressure. Often, the pres- sure reduction from cataract surgery alone is insufficient to meet our patients' needs. The 2-year COMPASS trial showed significant additive intraocular pressure lower- ing as well as significant re- duction in the requirements for topical medications with a safety signature that was similar to cataract extraction by itself. 1 These data, which carry out to 2 years with- out a degradation in the procedure's value, show us that the risk-to-benefit ratio of performing supraciliary micro-stenting in combina- tion with cataract surgery in patients with mild to moder- ate open-angle glaucoma is indeed favorable. It is always important for patients to understand the procedure they are having and the risks and benefits. My patients have been excit- ed at the prospect of getting better glaucoma control and reducing their eyedrop burden along with the bur- den of the side effects from drops. In my discussion with patients, I have found that they are open to the idea of internally draining the fluid and using a micro-stent to do so. Typically, patients will have concerns with drains that are external to the eye because they know that they can be seen and felt. I have been impressed with patient acceptance and excitement about this approach. n Reference 1. 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. Please see page 4 for Important Product Information. Nathan Radcliffe, MD, is in practice at NYU Langone Medical Center in New York City. He is a consultant for Alcon and received compen- sation for his contribution to this supplement. He can be reached at drradcliffe@gmail.com. Sponsored by

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