Eyeworld

68 | EYEWORLD | MAY 2020 G UCOMA by Ellen Stodola Editorial Co-Director D uring the 2020 American Glaucoma Society (AGS) Annual Meeting, a joint symposium with ASCRS fo- cused on the "Influence of Glauco- ma Surgery on Cornea." Endothelial loss Malik Kahook, MD, discussed "Managing En- dothelial Loss After MIGS Procedure." Endothelial cell loss (ECL) with trabeculec- tomy occurs around 9.5–14.5% of the time, he said, while it occurs in 8–24.6% of tube shunts. ECL is a bit higher but statistically similar between trabecular bypass devices combined with cataract surgery vs. standalone cataract surgery, with up to 3 years of follow-up, he said, noting that the XEN Gel Stent (Allergan) hasn't been correlated with ECL to date. Dr. Kahook discussed the recall of CyPass (Alcon) and intervention guidelines from the ASCRS Task Force. For eyes with 0 or 1 ring of the CyPass de- vice visible in the anterior chamber by gonios- copy, without clear evidence of corneal decom- pensation, the consensus was that no action other than clinical monitoring is recommended. For eyes with 2 or 3 rings of the CyPass device visible in the anterior chamber, there is a greater risk of corneal ECL. However, not all eyes in this category will experience clinically meaningful ECL, he said. Without clinically sig- nificant evidence of corneal decompensation, no action other than monitoring is indicated. If corneal decompensation develops and more than 1 ring of the device is visible, the surgeon may consider CyPass repositioning, removal, or proximal end trimming. He added that repositioning the device for deeper implan- tation would be most safe if performed within 7–10 days of implantation. Device removal, on the other hand, is generally not favored due to fibrosis that can make removal difficult. Trim- ming of the proximal end is likely the preferred procedure if the patient and physician desire intervention. Dr. Kahook recommended the following with CyPass today: repeat ECL testing, repeat it again, watch for changes in corneal thickness, identify if the patient is symptomatic, avoid trimming unless the patient has consistent ECL and shows changes in corneal thickness, educate the patient about cell loss with any intraocular surgery, and get a second opinion. Douglas Rhee, MD, spoke about manag- ing endothelial loss after traditional glaucoma surgery. Dr. Rhee noted that when looking at data after trabeculectomy and tube shunts, you should be aware of short follow-up in the literature. He covered some of the risk factors. With trabeculectomy, these include iridocorneal touch, pseudoexfoliation, and uveitic glaucoma, use of mitomycin-C, and higher degree of loss in the cornea by the bleb. With tube shunts, these include pseudoexfoliation and narrow tube-cornea angle on OCT. In terms of managing risk factors with tra- beculectomy, the number one thing is to avoid hypotony to avoid losing endothelial cells, Dr. Rhee said. Intervene quickly when hypotony oc- curs, and be aware of greater risk of ECD loss in pseudoexfoliation and uveitic glaucoma. For tube shunts, Dr. Rhee stressed the importance of keeping the tube away from the cornea and planar to the iris. He suggested a slit lamp examination to as- sess for focal or diffuse corneal stromal edema and/or presence of guttata. To further monitor corneal health, Dr. Rhee suggested corneal thickness and specular microscopy. Astigmatism Alan Robin, MD, discussed how glaucoma pro- cedures can create astigmatism. He said that 72% of patients have some astigmatic shift. It starts with steepening of the vertical meridian. Most will return to normal by 3 months, but some persist for greater than 12 months. Factors in this shift may include size and location of incisions, antimetabolites, cautery, flap, ostomy, and sutures/removal. Recap of the ASCRS symposium at the 2020 AGS Annual Meeting About the doctors Davinder Grover, MD Glaucoma Associates of Texas Dallas, Texas Malik Kahook, MD UCHealth Sue Anschutz-Rodgers Eye Center University of Colorado Aurora, Colorado Douglas Rhee, MD University Hospitals/Case Western Reserve University Cleveland, Ohio Alan Robin, MD Associate professor of ophthalmology and international health Johns Hopkins University Baltimore, Maryland Laura Voicu, MD Ophthalmic Consultants of Boston Boston, Massachusetts

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