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EW GLAUCOMA 102 February 2018 Presentation spotlight by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer tip. If a tube is too long, it can be trimmed. You can do this internally or make a paracentesis to pull the tube out and trim it externally. If the patient has a high functioning filter, you may see a lot of fluid going through the trab site during the surgery. This overfiltration can cause significant chemosis and may require a cut down of the conjunc- tiva to aid in your view. You want to create a nice sized capsulorhexis to avoid any phimosis. If the pupil is not well dilated, you may need to use rings or hooks, which may increase your inflammation postop- eratively, and you may require more aggressive steroids for treatment." Although in-the-bag IOLs are surgeons' first choice, they may need to fall back on sulcus or other lens implantation, depending on the state of the capsular bag and zonule fibers. Patients with trabe- culectomy and peripheral iridecto- my require careful haptic placement to avoid their migration into the anterior chamber. Anterior chamber lenses should be avoided in trab patients because they can cause me- chanical disruption of the bleb itself as well as fibrosis and inflammation later. During surgery, carefully remove all nuclear fragments to prevent occlusion of the ostium or tube. Careful removal of the pupillary dilation devices should be performed as well as thorough OVD removal to avoid intraocular pressure spikes postoperatively. In patients who tend to have vitreous loss, a complete anterior vitrectomy is advisable, so as not to cause any blockage of the ostium or the tube tip. "You want a nice, watertight closure here," Dr. Chaku said. "Often we suture these patients so there is no concern for wound leak. If you have a wound leak, you are diverting flow from the bleb itself to the wound, and that can increase the risk of bleb failure later as well." Postop concerns "In these patients, we worry about postoperative bleb failure," Dr. Chaku said. Some of the reasons for surgical planning, Dr. Chaku ex- plained. For instance, surgeons ac- customed to using the femtosecond laser may consider phaco instead, as the presence of a bleb may preclude suction ring adherence. Hypotony associated with a filtration bleb can substantially vary intraocular lens measurements. Patients with preex- isting glaucoma and multiple intra- ocular surgeries may have increased risk of endothelial cell loss preop- eratively, putting them at a higher risk for postoperative corneal edema and decompensation. Overall, it is important to determine what controlled the intraocular pressure and the function of any preexisting glaucoma surgery when planning surgery for these patients. "Cataract surgeons may need to revise the trab at the same time as cataract surgery if it is not func- tioning well," Dr. Chaku said. "Bleb needling can be done internally through a gonioscopic view by lift- ing up the flap internally or exter- nally, with or without the use of an antimetabolite. If the patient has a functional tube, it may need to be trimmed if it is sitting on the lens capsule, which improves access to the cataract. Typically, after cataract surgery on a patient with a pre-exist- ing tube, I flush the tube to decrease the risk of functioning at the end of the surgery." Intraop concerns Instrumentation poses additional concerns in patients with previous glaucoma surgery or tubes. "We need to protect the trabeculecto- my, especially if the bleb is thin and cystic. This starts with careful placing of the lid speculum," Dr. Chaku said. "Some people place OVD on the top of the bleb during surgery. When you are making your wound, incision, and paracentesis, and using a second instrument, be careful not to disrupt the trab itself. During cataract surgery, the anterior chamber needs to remain stable. It may be harder to maintain anterior chamber stability, particularly in patients with a high functioning filter. Increasing the bottle height can help with this as can using more OVD at this time. If the patient has a preexisting tube, you want to make certain not to block the tube sclerotic cataract with a posterior subcapsular component. She had a deep anterior chamber, poor dila- tion of 4 mm, advanced cupping on the optic nerve, and a flat retina. Preop concerns "The surgical plan for this patient consisted of complex cataract surgery of the right eye, with poor dilation, but entailed much more," Dr. Chaku said. "Many things came into play at once. It was very important to determine the cause of her blurry vision, whether it was her advanced glaucoma or progres- sion of her cataract. The patient's visual potential was assessed using a potential acuity meter to determine what her visual potential would be postoperatively, and help manage outcomes and expectations for the patient. We also realized that if the patient's pupil did not dilate well, she would likely need some sort of iris manipulation, which could lead to increased inflammation postop- eratively and ultimately increase her risk of bleb failure. Sometimes patients with peripheral iridotomy have zonular instability or vitreous loss in that area, which needs to be assessed preoperatively. Any patient with pseudoexfoliation has the po- tential to have weak zonules, which has the same risks and concerns." The degree of glaucoma damage and type of preexisting glaucoma surgery can weigh in on cataract Glaucoma specialist shares decision-making process in a complicated cataract case with previous trab O ften cataract surgeons are presented with patients whose ophthalmic history involves several moving parts. Preexisting con- ditions will affect different stages of cataract surgery and need to be addressed individually to ensure the best possible outcomes for the patient. Speaking at the 2017 ASCRS•ASOA Symposium & Con- gress, Meenakshi Chaku, MD, as- sistant professor of ophthalmology, and director of the glaucoma service, Loyola University, Chicago, shared a complicated cataract scenario. Dr. Chaku reported on the case of a 66-year-old female patient who presented at her clinic with blurry vision and glare in her right eye, whose visual acuity tested at 20/40 for distance and near. The patient had a history of advanced prima- ry open angle glaucoma, with a superior temporal Baerveldt implant (Johnson & Johnson Vision, Santa Ana, California) that was performed in 2013, and a superior nasal flat trabeculectomy, performed in Nige- ria, with a peripheral iridotomy. She was on three glaucoma medications and had an IOP of 14 mm Hg. The patient's cataract was a 3+ nuclear Planning cataract surgery in a patient with previous trabeculectomy A cystic bleb as shown here limits the placement of the main incision and LRIs. Source: Meenakshi Chaku, MD continued on page 104

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