Purpose: The aim of this study is to evaluate the functional and anatomical effects of switching from Bevacizumab to Aflibercept in patients with persistent DME resistant to Bevacizumab.

Methods: Patients with DME refractory to Bevacizumab (1.25 mg/ 0.05 mL) were subsequently switched to Aflibercept (2.0 mg/0.05 ml). The included patients received 5 loading doses of intravitreal Aflibercept (2.0 mg/0.05 mL) (Eylea; Bayer, Berlin, Germany) given monthly. After the loading dose, Aflibercept was injected every 2 months. The follow up duration was one year.

Inclusion Criteria:

• diabetic patients, older than 18years,
• center-involving DME, central macular thickness (CMT) >300 μm by spectral domain optical coherence tomography (SD-OCT) 1 month after the last Bevacizumab injection.
• The best corrected visual acuity must be better than 0.05 decimal visual acuity (1.3 log MAR). Only one eye from each patient was included in the study. If both eyes met the inclusion criteria, the eye with worse visual acuity was included.

Exclusion Criteria:

• Patients were excluded if they had dense media opacity, pregnancy, previous intravitreal steroid therapy.
• uncontrolled diabetes mellitus (HbA1c ≥ 10%) and prior intraocular surgery (with the exception of uneventful cataract surgery >6 months prior to conversion).
• Other exclusion criteria included active proliferative diabetic retinopathy, tractional maculopathy, macular ischemia and other ocular diseases: age-related macular degeneration, central/branch retinal vein occlusion, and glaucoma.

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