Diabetic Macular Edema (DME) Treatment With Ranibizumab and Dexamethasone or Ranibizumab Only.

Inclusion Criteria: Patients with diabetic retinopathy and centre involving DMO, as determined by using spectral domain optical coherence tomography (SD-OCT), in one or both eyes with: 1. Central retinal subfield thickness of \> 300 but \< 400 microns as determined by SD-OCT due to diabetic macular oedema OR 2. Central retinal subfield thickness of \< 300 microns provided that intraretinal and/or subretinal fluid is present in the central subfield (central 1 mm) related to diabetic macular oedema AND 3. Visual acuity of \> 24 Early Treatment Diabetic Retinopathy Study (ETDRS) letters (Snellen equivalent \> 20/320) 4. Amenable to laser treatment, as judged by the treating ophthalmologist 5. Over 18 years of age Exclusion Criteria: Eyes of patients will not be included in the study if: 1. The macular oedema is due to causes other than diabetic macular oedema such as epiretinal membrane, vitreomacular traction, vein occlusion, or others 2. The eye is ineligible for macular laser treatment, as judged by the treating ophthalmologist 3. The eye has DMO and central subfield retinal thickness (CST) of \> 400 microns. 4. The eye has activeA proliferative diabetic retinopathy (PDR) requiring treatment. 5. The eye has received intravitreal Anti- Vascular Endothelical Growth Factor (Anti-VEGF) therapy within the previous two months. 6. The eye has received macular laser treatment within the previous 12 months. 7. The eye has received intravitreal injection of steroids. 8. The eye has received cataract surgery within the previous six weeks 9. The eye has received panretinal photocoagulation within the previous 3 months 10. Patients on pioglitazone and the drug cannot be stopped 3 months prior to entering into the trial and for the duration of the study 11. The patient has chronic renal failure requiring dialysis or kidney transplant 12. The patient has any other condition that in the opinion of the investigator would preclude participation in the study (such as unstable medical status or severe disease that would make it difficult for the patient to be able to complete the study) 13. The patient has very poor glycemic control and started intensive therapy within the previous 3 months 14. The patient will use an investigational drug during the study