The evaluation of diabetic retinopathy is often difficult, because the clinical picture is complex due to the mUltiplicity of symptoms. Omission of treatment by photocoagulation at the right moment may have grave consequences. Forthe evaluation of diabetic retinopathy we have to estimate first the developmental degree of each symptom and secondly we have to estimate what the natural history of each particular retinopathy will be. There exists a number of classification systems, into the frame of which the clinical picture of diabetic retinopathy can be placed. Without entering into the...