November 2016

 

WORLD VIEW

 

Myriad of moving parts


 
 


Reay Brown, MD, glaucoma editor

 

When a cataract patient also has glaucoma, the complexity of surgical planning can escalate quickly. One of my doctors reminded me that when a patient has one unusual thing, they are more likely to have others. For example, I’ve found that glaucoma/cataract patients commonly will also have epiretinal membranes. Add a small pupil, IFIS, a shallow chamber, and some astigmatism, and there is a myriad of moving parts. Fortunately, our options and tools have improved dramatically as glaucoma surgeons seek to achieve outcomes in complex patients that rival the rapid recoveries and excellent vision reported by patients without glaucoma.

I started practice when the lingering effects of pilocarpine were still causing small and bound down pupils in glaucoma patients. Two decades ago the predominant treatment for these permanently small pupils was a sector iridectomy. As pilo fell out of favor as a glaucoma treatment, it looked like pupil problems were disappearing, with the large exception of pseudoexfoliation. Then IFIS emerged and pupil issues were back with a vengeance. We are fortunate to have Bradford Shingleton, MD, Paul Harasymowycz, MD, and Parag Parekh, MD, offer insight on how to handle these difficult cases. We’ve come a long way from sector iridectomies and now can choose from a variety of rings and hooks. It’s even often possible to leave the iris looking like it was normal to begin with.

Shallow chambers are another area of immense progress. Perhaps the greatest game-changer is the dry pars plana vitrectomy. A few seconds of vitrectomy can transform an impossibly shallow chamber into a deep chamber, greatly reducing the risk of the surgery. David Crandall, MD, and Lama Al-Aswad, MD, share their tips on handling these challenging cases. My personal record for a short eye was 15.0 mm. I piggybacked two 30 D lenses and the patient was still slightly hyperopic. The eye was very small overall, but the chamber was not particularly shallow. On the other hand, I recently had a patient with an intumescent lens and an axial length of 22.4 mm, but with an almost nonexistent chamber. The dry vitrectomy allowed the chamber to deepen and the case proceeded uneventfully.

Cataract surgery offers surgeons a great opportunity to help their glaucoma patients with safe MIGS procedures. The adoption rate for surgeons either using or wanting to start using the iStent (Glaukos, San Clemente, California) has already reached 50%, according to a recent ASCRS survey. Richard Lewis, MD, Jason Bacharach, MD, Arsham Sheybani, MD, Steven Sarkisian, MD, and Constance Okeke, MD, review the many MIGS options that can be combined with cataract surgery. The increasing collective experience has improved our ability to find the trabecular meshwork and Schlemm’s canal, and this will result in better outcomes. There is still an important group of glaucoma patients who need glaucoma surgery alone; they may already be pseudophakic or phakic without cataract. Ronald Fellman, MD, Ramesh Ayyala, MD, Steven Gedde, MD, Leonard Seibold, MD, and H. George Tanaka, MD, share their expertise in these sight-saving operations. Over the past decade, the controversy has been about whether to perform a tube shunt or trabeculectomy. Now there are several new options, with more on the way. We also anticipate the approval of the Xen Gel Stent (Allergan, Dublin) and the InnFocus (Miami) MicroShunt as direct alternatives to trabeculectomy. Both devices offer the promise of safer and more controlled external drainage procedures.

We hope that the tools, techniques, and tips discussed in these articles can help you navigate these challenging waters. Our glaucoma patients expect to have excellent outcomes, and most of the time we can meet their high expectations.

Myriad of moving parts Myriad of moving parts
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