EWAP DECEMBER 2022 31 GLAUCOMA talk from a fellow physician who presented a 20% rate of intractable elevation in IOP when injecting bevacizumab. With further exploration into this, Dr. Mandava said he hasn’t seen levels that high, but he shared similar comments as Dr. Kahook about how certain compounding pharmacies seem to have issues, likely due to silicone oil microdroplets in the syringes. This led to further research, as well as conversations with many large pharmacies. As such, changes have been made to ensure the drug is transferred appropriately. Dr. Mandava added that the way that these syringes were transported on dry ice was also a concern because the drug could freeze and thaw during travel time. “Our multidisciplinary group of clinicians and scientists in ophthalmology and the pharmaceutical sciences was the first to elucidate the cause of intractable elevation of intraocular pressure in patients receiving these therapies,” he said. “This research led to changes in compounding pharmacy practices, which has decreased the incidence of these complications.” Risk factors Dr. Weng said that if the patient has ocular hypertension, a diagnosis of glaucoma at baseline, or other risk factors for developing glaucoma, the risk for post-injection IOP elevation is higher. “Ocular characteristics such as lens status and axial length have been explored without definitive correlation established,” she said. “As we age, the sclera becomes increasingly rigid, which could also theoretically contribute to IOP elevation.” Dr. Weng added that another factor that seems to increase risk is the frequency or cumulative number of injections that a patient has received. With regard to the medication itself, this is unclear. In one IRIS Registry study of 23,776 patients, on average, 2.6% sustained a clinically significant IOP rise with anti-VEGF drugs overall compared to 1.5% in the fellow untreated eye, Dr. Weng said. However, this difference was not observed with the aflibercept subgroup compared to the bevacizumab and ranibizumab subgroups.3 Dr. Kahook said his studies have shown that the incidence of IOP spikes was much higher in patients with preexisting glaucoma. In one study, they found patients with preexisting glaucoma experienced higher rates of elevated IOP when compared to patients without preexisting glaucoma (33% vs. 3.1%, respectively; p<0.001).4 Clinicians should treat patients with extra caution when they require anti-VEGF injections in the setting of co-existing glaucoma and retinal pathology. “Added vigilance to check IOP post-injection and routine check of pressure with Goldmann applanation is key,” he said. “When patients are seen in injection clinics, it is imperative that they receive pressure checks as part of the routine workup, something that is not done across the board.” Minimizing risk If there is a patient in whom avoidance of an IOP spike is critical, Dr. Weng said the retina specialist could consider performing a pre-injection anterior chamber paracentesis and prescribing prophylactic IOP-lowering drops. “Additionally, pre- and post-injection IOP measurements as well as close tracking temporally may provide insights into whether a change in treatment frequency or a switch in anti-VEGF agent should be considered.” Dr. Mandava said he will always check the pressure before doing an injection. If the pressure is mildly elevated, he will move forward. But if it’s elevated into the mid-20s or higher, he thinks about what the cause may be, examines the eye and drainage system, makes sure there are no other issues, and looks at optic nerves to see if there’s any evidence of asymmetry. If it’s above a certain pressure, he may withhold the injection, start the patient on topical medication, and see them back for the injection. Injections in the setting of MIGS/other glaucoma procedures For those with a history of MIGS/glaucoma surgery, there is no consensus on whether to modify the injection or pre-injection approach, Dr. Weng said. “I am always mindful of where trabeculectomy blebs or tube shunt plates are located and avoid injecting through these areas, but I do not currently do anything differently for these patients aside from reminding them to continue with regular follow-up with their glaucoma specialist and monitoring their pre-injection IOP each time they come to see me,” she said. Dr. Weng said she also likes to involve a glaucoma specialist any time she is concerned that an injection-associated
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