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Nisha Gupta, Muneera Mahmood, Christopher Leffler, Vikram Brar; Effect of Bevacizumab, Ranibizumab, and Aflibercept injections on retinal nerve fiber layer (RNFL) thickness in patients with diabetes and macular edema. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):218. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Numerous clinical trials have established the efficacy of anti-VEGF therapy for diabetic macular edema, where injections of various agents reduced macular edema and increased visual acuity. VEGF has been shown to delay oxidative stress mediated neuronal loss in animal models of ALS. Oxidative stress has been implicated in the pathogenesis of diabetic retinopathy as well. Thus, long term blockade of VEGF-A may have deleterious effects on the retina. In vitro studies have demonstrated a protective effect of VEGF on ganglion cells treated with hydrogen peroxide. This effect was neutralized by the co-treatment with bevacizumab. Our study aims to study the effect of anti-VEGF therapy in vivo, by monitoring the retinal nerve fiber layer in diabetic macular edema patients.
Patients with diabetic macular edema deemed to require anti-VEGF therapy who were treatment naïve were included. Those with prior optic neuropathy, glaucoma suspect, ocular hypertension, glaucoma, or significant media opacity were excluded. The RNFL thickness, using Heidelberg Spectralis®, was measured before treatment and then 1, 3, and 6 months thereafter using image registration at follow up scans. The number of injections and global thickness as well as the RNFL thickness of each quadrant were recorded and analyzed using the paired t-test to compare each testing interval with the pre-injection data. The primary outcome focused on changes in global thickness over time.
Thirty patients were included in the study. Three patients received treatment with aflibercept, two with bevacizumab, and 25 with ranibizumab. The average number of injections was 2.2. The average global thickness was: Baseline: 99, 1M: 93.8 (p-0.025), 3M: 91.3 (p-0.031), 6M: 92.4 (p-0.027). There was no significant change in intraocular pressure over the follow up period as well, with an average of 16 at baseline and after 6 months.
There was a trend towards reduction in the global score in the RNFL analysis, which achieved statistical significance through 6 months of follow up. Therefore, anti-VEGF therapy was not shown to have a deleterious effect in vivo on the retina.
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