Eyeworld

DECEMBER 2021 | EYEWORLD | 85 G Contact Myers: JMyers@willseye.org Razeghinejad: razeghinejad@yahoo.com Smith: tsmith@glaucomaassociates.com plate covered after the capsule is violated due to epithelialization within it. However, if it's tube exposure over the tubing material, Dr. Smith said the approach is usually to go in and open the conjunctiva. "It's important to cauterize any epithelial tissue that would have grown into and around the tube subconjunctivally." Conjunctival closure may be a challenge in certain instances, so tissue mobilization, the use of amniotic membranes, conjunctival graft, or pedicle flap are ways of achieving adequate coverage. 9 Dr. Smith said she tends to move the tube position as well because she thinks there is some mechanical effect that has a part to play in why the tube was exposed in that location. She usually moves the tube over about one clock hour toward 12 o'clock. Snaking and securing tube material during primary tube surgery as she directs the tube to the 12 o'clock position leaves extra tubing available for relocation of the entry point in the future if this is needed. Patch graft material or method is another discussion, she said. Whether you put a patch graft or create a long track for the tube as it enters the eye, as you revise, you should try to use patch material to cover the tube to prevent re-exposure. Most patients do well with tube revision. There are some extreme instances with se- vere infection or where the tube is completely expelled in which vision is significantly threat- ened, Dr. Smith said, but in most instances, patients recover fully following a revision with maintenance of pre-exposure IOP if it was just an exposed tubing. "When we think about exposed hardware in other parts of the body, often they remove that hardware," Dr. Myers said. "In most cases, even those cases of infection, we don't remove or replace the tube." If tube position is good in the anterior chamber and on the sclera, and if it's not too close to the limbus, the surgeon can patch over the tissue and reclose the conjunctiva and not have another erosion in the vast major- ity of cases. "If we see something that predisposes to erosions, like the tube shunt is a little too anterior in insertion or if it has a laxity to it so the tube bows up, most of us would reposition," Dr. Myers said. "But for most of the patients, another patch graft on top, deepithelialize the Relevant disclosures Myers: Aerie, Avisi, Allergan, Equinox, Glaukos, Guardion Health Sciences, Haag-Streit, MicroOptx, Nicox, Olleyes, Santen Razeghinejad: Olleyes Smith: New World Medical "When we think about exposed hardware in other parts of the body, often they remove that hardware. In most cases, even those cases of infection, we don't remove or replace the tube." —Jonathan Myers, MD area with cautery, and make sure that fresh conjunctiva is brought down that's not under tension." Even with long-term follow up, it's rare the patient gets a second erosion, he said, though he noted it can happen. "I think in any patient who has an infection and erosion, you have to assume it's from the erosion," Dr. Myers said. The erosion is usually easy to identify, but he added that non-glauco- ma specialists may not be specifically looking for this. Dr. Myers added that the further back from the limbus that the tube is inserted, the less likely it is to have erosion. A tube that's placed in the sulcus, in general, tends to enter the eye more posterior. A tube in the pars plana is even more posterior. "When it doesn't extend as far anterior to the limbus, I think the risk of erosion is much smaller," he added. Dr. Myers said it's always a balance of pros and cons. People with good tissue do better, and the better the placement, the better they tend to do, but there are some patients who still run into problems. Eyes that had prior surgery and those with tissue and surface issues are more at risk as well, he said. Careful vigilance in eyes with prior tube shunt surgery will identify erosions early before serious problems arise in most cases.

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