Update and implications from the Newcastle diabetic retinopathy study.

Over 11 years from 1977 a large study of diabetic retinopathy has been conducted in Newcastle and in 1988, 5519 diabetic subjects had been assessed. Where possible, all had retinal photography. Prevalence rates for any retinopathy, proliferative retinopathy and maculopathy were assessed in relation to the known duration of diabetes for subjects diagnosed before or after age 30 years. These data indicate a peak of retinopathy prevalence in the second or third decade of diabetes with slightly lower rates in longer survivors. Treatment with insulin was associated with a higher retinopathy prevalence. Incidence rates for the new development of background retinopathy in previously unaffected subjects show a peak late in the first decade of diabetes in young-onset cases, while in the older-onset group, the peak occurs in the second decade of diabetes. Over all, 8% of diabetics without retinopathy developed it per year. The implications of this data for the routine management of diabetic patients is discussed and the current recommendations for retinal screening by the Australian Diabetes Society are outlined.