Clinical Use of Dexamethasone Implants in Resistant Macular Edema Secondary to Branch Retinal Vascular Occlusion Compared with Intravitreal Anti-Vascular Endothelial Growth Factor

INTRODUCTION: Branch retinal vein occlusion (BRVO) is the second most common type of retinal vascular disorder. Both inflammation and increased vascular endothelial growth factor (VEGF) levels play important roles in the pathogenesis of macular edema (ME) secondary to BRVO. The aim of this study was to compare the efficacy of 0.7-mg intravitreal dexamethasone implants with continued anti-VEGF treatment in patients with ME secondary to BRVO who were poor responders to at least 6 previous anti-VEGF injections.
METHODS: Patients exhibiting an insufficient response to at least 6 ranibizumab treatments and who subsequently underwent a dexamethasone implant were included Group 1. Patients who were at risk for cataract or glaucoma continued treatment with the same drug and were defined as Group 2. The best corrected visual acuity (BCVA) and central macular thickness (CMT) changes at month 2, 4, and 6 were measured.
RESULTS: Ninety eyes were evaluated. In Group 1, the mean baseline BCVA of 0.71±0.75 logarithm of the minimum angle of resolution (logMAR) improved to 0.53±0.62 logMAR at month 2 (p<.001), 0.67±0.72 logMAR at month 4 (p=0.325), and 1.03±0.83 logMAR at month 6 (p=.001). In Group 2, the mean baseline BCVA was 0.73±0.83 logMAR, and improved to 0.68±0.83 logMAR at month 2 (p=0.12), 0.698±0.81 logMAR at month 4 (p=0.270), and 0.76±0.80 at month 6 (p=0.546). The baseline CMT in each group was 588±176 μm and 545±165 μm, respectively (p=0.248). The mean CMT of Group 1 changed from a baseline measurement of 588±176 μm to 308±132 μm at month 2 (p<.001), 450±195 μm at month 4 (p<.001), and 510±190 μm at month 6 (p<.001). The mean CMT of Group 2 changed from a baseline value of 545±165 μm to 486±162 μm at month 2 (p<.001), 516±168 μm at month 4 (p<.001), and 528±171 μm at month 6 (p=0.037).
DISCUSSION AND CONCLUSION: Dexamethasone implants were a more effective treatment for patients with BRVO-related resistant ME than ranibizumab at month 2. However, this positive effect seems to decline rapidly in the long term.