Efficacy of Intravitreal Dexamethasone Implant in the Treatment of Macular Edema Secondary to Retinal Vein Occlusion and Resistant to Intravitreal Ranibizumab Injection

Abstract

INTRODUCTION: Retinal vein occlusion (RVO) is the second most frequent retinal vascular disease after diabetic retinopathy. Macular edema secondary to RVO is the most prevalent cause of visual loss. The aim of this study was to evaluate the efficacy of intravitreal dexamethasone implant (IVDI) in the treatment of macular edema secondary to RVO and refractory to at least three months of repeated intravitreal ranibizumab injection (IVRI). METHODS: Forty-two eyes of 42 patients who were admitted with RVO to the Department of Ophthalmology, University of Health Sciences, Istanbul Fatih Sultan Mehmet Training and Research Hospital between January 2016 and January 2018 and underwent IVDI for refractory macular edema despite repeated IVRI for at least three months were included in the study. Best corrected visual acuity, intraocular pressure and mean central macular thickness were retrospectively compared at the first, second, third and sixth months after IVDI. RESULTS: The best corrected visual acuity before IVDI was 0.83+-0.48 'Logarithm of Minimum Angle of Resolution' (LogMAR). After IVDI, the best corrected visual acuity happened as 0.55+-0.42 LogMAR at the first month, 0.52+-0.43 LogMAR at the second month, 0.62+-0.47 LogMAR at the third month and 0.75+-0.54 LogMAR at the sixth month. Mean central macular thickness before IVDI was 550+-156.53 µm. Mean central macular thickness after IVDI evaluated as 427.53+-165.52 µm in the first month, 382.8+-156.48 µm in the second month, 382.35+-160.37 µm in the third month, and 435.83+-176.57 µm in the sixth month. A statistically significant increase in best corrected visual acuity and a statistically significant decrease in mean central macular thickness were reported at the first, second and third months after IVDI compared to before IVDI. DISCUSSION AND CONCLUSION: It was observed that IVDI provided an increase in best corrected visual acuity and a decrease in central macular thickness in the treatment of macular edema due to RVO and assessed that repeated injections are needed to maintain this gain. Long-term results are needed to determine whether the inter-injection interval will decrease with repeated injections and whether both intraocular pressure increase and cataract development will change.

Keywords

• anti-vascular endothelial growth factor
• intravitreal dexamethasone implant
• intravitreal ranibizumab injection
• macular edema
• retinal vein occlusion.