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The use of anti-vascular endothelial growth factor agents in patients with neovascular age-related macular degeneration has revolutionized the treatment of this disease, but concerns about the increased risk for elevated IOP with these agents continue to trouble ophthalmologists.
"Intravitreal ranibizumab [Lucentis, Genentech] and bevacizumab [Avastin, Genentech] have dramatically improved our treatment outcomes in eyes with neovascular AMD," said Dr. Freund, clinical associate professor, New York University School of Medicine, and attending surgeon at Manhattan Eye, Ear and Throat Institute, NY. "Several recent reports suggest that sustained ocular hypertension can occur in a small percentage of eyes receiving intravitreal ranibizumab or bevacizumab therapy. The cause of these sustained IOP elevations remains elusive, but several potential mechanisms have been considered."
Dr. Freund reviewed some of these studies.
■ In 2008, in a case series by Bakri et al. the authors concluded that four patients had elevated IOP after intravitreal ranibizumab (0.5 mg). None of these patients had a previous history of glaucoma, ocular hypertension, or IOP asymmetry. IOP reached levels of 30, 34, 46, and 50 mm Hg in these patients.1
■ In their retrospective case series, Kahook et al. reported that all six patients experienced significant and sustained IOP elevation after single or repeat intravitreal injections of bevacizumab, and required IOP-lowering therapy.2
■ In 2010, Adelman et al. reported that four out of 116 patients with AMD (3.45%) developed sustained elevated IOP after multiple injections of intravitreal bevacizumab (1.5 mg/0.06 ml) and/or ranibizumab (0.5 mg/0.05 ml).3
Dr. Freund discussed an analysis he and his colleagues recently completed looking at data from 474 eyes of 349 patients treated with intravitreal anti-VEGF therapy of over a 6-month period. All eyes were being treated for neovascular AMD and had received a minimum of three injections. The investigators found that 39 of 474 eyes (8.2%) had sustained IOP elevations during treatment, defined as IOP >22 mm Hg on two consecutive office visits and/or the initiation of IOP-lowering intervention due to IOP elevation. A multivariate analysis showed that the total number of injections was what correlated best with the probability of experiencing a sustained IOP elevation (p = 0.0004).5
This issue cannot be ignored because it can lead to damage of the optic nerve head as well as vision loss. Another important consideration is that most patients being treated for AMD are elderly and already at a higher risk for glaucoma.