Incidence of diabetic retinopathy increases over time

Percent of patients with diabetic retinopathy according to duration of disease in patients under the age of 30 years who were treated with insulin (primarily type 1 diabetes) and patients over the age of 30 years who were not treated with insulin (primarily type 2 diabetes). Retinopathy increased over time in both groups, affecting virtually all patients with type 1 diabetes by 20 years. The increased incidence in type 2 diabetes at 3 years is a probable reflection of the difficulty in determining the time of onset of that disease.