37 EyeWorld Asia Pacific | June 2024 Dr. Weng said it’s also unclear if the frequency of injections has an impact. “Obviously, if a true relationship exists between injections and persistent IOP spikes/glaucoma progression, then those receiving injections at a greater frequency would be at greater risk. It’s an area of active investigation,” she said. To help reduce potential risk to glaucoma patients having intravitreal injections, Dr. Weng said that pre-injection IOP should be noted and tracked over time for all patients. “For patients with glaucoma or who are susceptible to glaucoma, the retina specialist could consider performing an anterior chamber paracentesis immediately before or following the injection,” she said. “Injecting more slowly has been suggested as a beneficial modification by some but lacks evidence at this time. Prescribing IOP-lowering drops to be used afterward is another option.” Dr. Weng noted that she rarely takes these steps personally but said that she always makes sure that her patients with glaucoma are actively being followed-up with for their condition and suggests having a low threshold to directly reach out to the glaucoma specialist. “Research shows that higher frequency of intravitreal injections may impact the need for glaucoma medication use and glaucoma surgery.6,15 Therefore, patients should routinely have their pressure checked whenever they present for an injection to monitor for IOP spikes and trends over time,” she said. Glaucoma patients should also be monitored with OCT and visual field testing with a glaucoma specialist. Dr. Schehlein said that IOP spikes should be prevented in patients with advanced glaucomatous disease, especially as large IOP fluctuations in these cases may worsen disease. “In patients with advanced disease, we know that repeated IOP fluctuations may worsen glaucoma.11,16 In an advanced glaucoma patient newly requiring IVI for neovascular AMD with demonstrated IOP spikes following injection, I am proactive in preventing progression,” she said. “Sometimes this will mean adding an additional drop (as this has been known to decrease post-IVI IOP spikes), but if the IOP elevation is sustained or the fluctuation is significant, I will also talk to patients about the risks and benefits of pursuing a minimally invasive glaucoma surgery to decrease IOP fluctuations and lower IOP in the long term.17 In the case of glaucomatous progression in any patient, I will consider both minimally invasive and incisional surgery as an option to reduce IOP.” While there are not many other complications associated with performing glaucoma procedures in patients who receive intravitreal injections, Dr. Weng did note the possibility of zonulopathy. “In those with an extensive history of intravitreal injections, because some glaucoma procedures nowadays are combined with cataract surgery, the surgeon should be aware of potential loss of zonular integrity,” she said. “One large registry study from Sweden found a 1.45 odds ratio for cataract surgery complications among patients with a history of intravitreal injections compared to those with none.”18 There have been recent advancements in drugs available in the retina space, as well as drugs being used in higher doses. It’s important to consider and monitor the impacts that these may have as they are being used and studied more. In 2023, the first two drugs for the treatment of Geographic Atrophy (GA) were approved by the FDA. These are complement inhibitors given as intravitreal injections either every month or every other month, Dr. Weng said. “Because of this frequency, along with the fact that the drug volume is 0.1 cc (double the typical injection volume), it is important to remain vigilant for any post-marketing adverse effects that may emerge,” she said. “The rate of IOP rise reported in the pivotal trials for Pegcetacoplan and Avacincaptad pegol ranged from 2–9% but were thought to be related to the injection procedure rather than the drug itself, and the majority were transient and self-resolved.”19 Dr. Weng added that some recently-approved and investigational drugs are administered in a greater volume than what has typically been injected. “High-dose Aflibercept is a four-fold dose of standard Aflibercept delivered in a 0.07 cc volume,” she said. “Given concerns for possible effects on IOP by these drugs and others, some retina specialists are applying pressure to the globe pre-injection to potentially prevent post-injection spikes, although the benefits of doing this are unproven.” She added that it will be important for retina specialists to monitor all patients’ IOP over time and work closely with their glaucoma colleagues as more is learned about the relationship between intravitreal injections and glaucoma. Dr. Schehlein said the effect on intraocular pressure after intravitreal injections occurs in two phases. First is the initial IOP spike from additional fluid injected into the eye, GLAUCOMA
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