Evaluation of Retinal Changes in Systemic Darbepoetin Alpha Treatment in Patients With Diabetes Mellitus

Inclusion Criteria: Group A: * Males and females aged 18 to 80 yrs * Diabetes mellitus type 1 or 2 * Haemoglobin level above the treatment threshold level (as described in the drug description) * Receiving no darbepoetin alfa treatment * Best Corrected Visual Acuity (BCVA) better than 20/200 * No clinically significant macular edema (CSME) or CSME already treated with laser photocoagulation. Group B: * Males and females aged 18 to 80 yrs * Diabetes mellitus type 1 or2 * Anaemia (due to renal failure), haemoglobin level under the treatment threshold level before the initialisation of the therapy (as described in the drug label) * Starting to receive darbepoetin alfa treatment (darbepoetin alfa, Aranesp, Amgen) * BCVA better than 20/200 * No clinically significant macular edema (CSME) or CSME already treated with laser photocoagulation. Exclusion Criteria: * History of retinal disease other than DR * History of intraocular surgery, including laser treatment in the past 4 month * A major change in the insulin treatment of the patient in the past 4 month or during the follow up period. * Inability to communicate in German or English * Dementia; inability to follow commands * Epilepsy