To determine if there is visual benefit with Ozurdex treatment every three months compared to monthly anti-VEGF alone, in subjects with persistent diabetic macular edema. The investigator hypothesizes more frequent administration of Ozurdex in patients that have persistent diabetic macular edema will result in a more rapid and sustained improvement of visual acuity and/or optical coherence topography (OCT) compared to the use of anti-VEGF alone.

Statistics throughout this study referred to the number of eyes rather than the number of subjects. Subjects were allowed to have both eyes in the study provided that inclusion/exclusion criteria were met. Five subjects had both eyes in the study; 45 subjects were actually enrolled, resulting in 50 study eyes.

Inclusion Criteria:

1. Male of female age 18 years or older
2. Type 1 or Type 2 diabetes
3. Best corrected visual acuity (BCVA) score of >24 and <78 letters
4. History of at least 3 anti-VEGF intravitreal injections over the past 5 months
5. Presence of macular edema defined as central subfield thickness of >340 microns on Cirrus OCT

Exclusion Criteria:

1. Anti-VEGF intravitreal treatment in the last 4 weeks
2. Intravitreal steroid treatment in the last 8 weeks or Ozurdex in the last 4 months
3. Pan retinal photocoagulation (PRP) or focal laser in the last 4 months
4. Active iris neovascularization
5. Any ocular condition in the study eye that, in the opinion of the investigator, is severe enough to compromise the study result
6. Uncontrolled systemic disease
7. Known history of intraocular pressure (IOP) elevation in response to corticosteroid treatment, that is not controlled on 2 glaucoma medications
8. Current enrollment in an investigational drug study or participation in such a study within 30 days prior to the baseline visit
9. Female patients who are pregnant, nursing or planning a pregnancy or who are of childbearing potential and not using a reliable means of contraception
10. Any condition or reason (including inability to read early treatment diabetic retinopathy study (ETDRS) chart or language barrier) that precludes the patient's ability to comply with study requirements including completion of the study
11. Patients with active or suspected ocular or periocular infections including most viral diseases of the cornea and conjunctiva, including active epithelial herpes simplex keratitis (dendritic keratitis), vaccinia, varicella, mycobacterial infections, and fungal diseases.
12. Aphakia or pseudophakia with anterior chamber intraocular lens
13. Hypersensitivity to any components of Ozurdex or Avastin