Retinal Ganglion Cell Function After Intravitreous Ranibizumab in Patients With Diabetic Macular Edema

Inclusion Criteria: * Male or female patients, older than 18 years, who have signed an informed consent. * Patients with Type 1 or Type 2 diabetes mellitus and prior diagnosis of diabetic macular edema (DME), who had not undergone any previous treatment, either pharmacological or laser photocoagulation. * Patients with visual impairment due to DME whom, in the opinion of the investigator, would benefit from treating with IVR. Exclusion Criteria: * Known hypersensitivity to ranibizumab or any of its components. * Previous participation in any clinical studies of investigational drugs within 1 month * Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, including women whose career, lifestyle, or sexual orientation precludes intercourse with a male partner and women whose partners have been sterilized by vasectomy or other means, UNLESS they are using two birth control methods. The two methods can be a double barrier method or a barrier method plus a hormonal method. Adequate barrier methods of contraception include: diaphragm, condom (by the partner), intrauterine device (copper or hormonal), sponge or spermicide. Hormonal contraceptives include any marketed contraceptive agent that includes an estrogen and/or a progestational agent. * Pregnant or nursing (lactating) women. * Inability to comply with study or follow-up procedures.