Characterization of Eyes With Diabetic Macular Edema That Show Different Treatment Response to Intravitreal Anti-VEGF (CHARTRES)

Inclusion Criteria: * Patients with 40 years of age or older. * Type 2 Diabetes Mellitus. * Glycosylated hemoglobin (HbA1C) ≤ 12% at screening visit. * Presence of clinically significant DME involving the center (fovea) diagnosed in at least one eye that is eligible for anti-VEGF treatment in the opinion of the investigator. If both eyes are eligible, the one with the worse visual acuity, as assessed at screening visit, will be selected as the study eye. * Visual impairment due to DME with BCVA ≥ 39 letters and ≤ 73 letters (≥ 20/160 and ≤ 20/40). * Central subfield thickness ≥ 300µm. Exclusion Criteria: * Presence of any other ocular disease than DME in the study eye that may confound study results, such as Proliferative Retinopathy. * Previous treatment with vitrectomy or intravitreous injections of triancinolone or anti-VEGF drugs in the study eye. * Any previous laser photocoagulation (panretinal or focal) in the study eye within 6 months prior to inclusion in this study. * Active intraocular inflammation (grade trace or above) in either eye at screening visit. * Any active infection (e.g. conjunctivitis, keratitis, scleritis, uveitis, endophthalmitis) in either eye at screening visit. * Important refractive errors (myopia \> 6D) or opacification of clear media that interferes with images evaluation. * Patients with renal failure or other systemic conditions which, in the opinion of the investigator, would preclude schedule study visits, completion of the study or a safe administration of study medication. * Other criteria that in the opinion of the investigator should condition the evaluation purposed.