Objective: To examine the 10-year incidence and progression of diabetic retinopathy.
Design: Population-based incidence study.
Participants: Seven hundred sixty-five insulin-taking diabetic persons diagnosed before age 30 years, 251 insulin-taking diabetic persons diagnosed at age 30 years or older, and 282 non-insulin-taking diabetic persons diagnosed at age 30 years or older who participated in baseline, 4-year, and 10-year follow-up examinations.
Main outcome measures: The 10-year incidence of any retinopathy, progression of retinopathy, and progression to proliferative retinopathy were detected by masked grading of stereoscopic color fundus photographs using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study severity scheme.
Results: The 10-year incidence of retinopathy (89%, 79%, and 67%), progression of retinopathy (76%, 69%, and 53%), and progression to proliferative retinopathy (30%, 24%, and 10%) were highest in the group diagnosed before age 30 years, intermediate in the insulin-taking group diagnosed at age 30 years or older, and lowest in the non-insulin-taking group, respectively. Increased risk of proliferative retinopathy was associated with more severe retinopathy at baseline.
Conclusions: These data suggest relatively high 10-year rates of incidence and progression of retinopathy, and despite changes in the treatment of diabetes, there has been little change in the incidence and progression of diabetic retinopathy during the 10-year study period.