To evaluate the efficacy of sequential therapy with intravitreal dexamethasone implant followed by bevacizumab compared with bevacizumab monotherapy for macular edema (ME) secondary to retinal vein occlusion (RVO).

Retinal vein occlusion is the second most common retinal vessel disease following diabetic retinopathy. It is divided into central retinal vein occlusion and retinal vein occlusion. Visual disturbance resulting from retinal vein occlusion is mainly caused by macular edema, and one of the main mechanisms of macular edema is increased vascular endothelial growth factor. Increased vascular endothelial growth factor is known to cause macular edema by breaking blood retinal barrier and causing leakage. For this reason, intravitreal injection of anti - vascular endothelial growth factors is currently used to treat macular edema due to retinal vein occlusion. Corticosteroid is a different mechanism from anti - vascular endothelial growth factor, and it is the main mechanism to suppress macular edema, to suppress the expression of inflammatory mediators, to block the inflammatory reaction pathway, and to lower the vascular endothelial growth factor concentration in the vitreous body. The dexamethasone implant in the vitreous cavity showed the maximum visual improvement effect during 60 day after one injection, and the effect continued until about 90 days after the injection. The same effect was obtained with a fewer injection times compared to the injection of the anti-vascular endothelial growth factor and a variety of inflammatory. It is also effective in patients who do not respond to anti-vascular endothelial growth factors by effectively inhibiting cytokines and growth factors. However, steroids elevated intraocular pressure, it is limited in repeated use.

Intravitreal dexamethasone implantation and anti-vascular endothelial growth factor showed similar early vision improvement. The differences in these anatomical changes may be different in long-term visual prognosis. After 3 doses of loading dose of anti-vascular endothelial growth factor, each group was injected with anti-vascular endothelial growth factor (VEGF) at each recurrence of macular edema and injected with anti-vascular endothelial factor at each macular reattachment after dexamethasone injection. The results of this study are as follows.

Inclusion Criteria:

Center-involved macular edema secondary to BRVO for no longer than 3 months (at the screening visit it should be ensured that the subjects will comply with the criterion of ≤ 3 months since onset of macular edema at their scheduled baseline visit).

Exclusion Criteria:

• Previous PRP or macular laser photocoagulation in the study eye.
• Any prior or concomitant ocular treatment (e.g. anti-VEGF therapy, corticosteroids) in the study eye for macular edema secondary to BRVO, except dietary supplements or vitamins prior to inclusion in the study. Intraocular anti-VEGF treatment is permitted for the treatment of diseases of fellow eye except for those that are specifically excluded.
• Prior systemic anti-VEGF or corticosteroid therapy, investigational or approved, within the last 3 months before the first dose in the study.
• Previous use of intraocular corticosteroids in the study eye at any time or use of periocular corticosteroids in the study eye within 12 months prior to Day 1.
• Any active intraocular, extraocular, and periocular inflammation or infection in either eye within 4 weeks of screening.
• Any history of allergy to povidone iodine.
• Known serious allergy to the fluorescein sodium for injection in angiography.
• Presence of any contraindications indicated in the EU commission/locally approved label for intravitreal aflibercept: hypersensitivity to the active substance intravitreal aflibercept or to any of the excipients; active or suspected ocular or periocular infection; active severe intraocular inflammation.