Despite the efficacy of laser photocoagulation as the treatment for diabetic retinopathy, this condition is the leading cause of blindness in developed countries. In this survey we have tried to find out whether this lack of effectiveness is due to a lack of adequate control and screening. As a proxy measure for this we have developed an indicator called "lateness" and we have followed a sample of diabetics drawn from the two public hospitals in Vizcaya (Spain). Seventy five percent of them were not at regular intervals and half of the sample was late for treatment. Among these, Insulin-dependent diabetics of older age and with more years of the disease are at a higher of entering late for treatment. We could not find any risk factor lateness among non insulin dependent diabetics. We concluded that most of diabetics are not adequately followed up for the prevention of diabetic retinopathy, and when they are referred to treatment it is too take the most advantage of it.