Thirty-Two Years Screening for Diabetic Retinopathy in a Single Centre: An Assessment of Visual Outcomes

Background/Objectives: Diabetic retinopathy (DR) is a leading cause of preventable visual impairment, and systematic screening is essential to detect sight-threatening stages before symptoms occur. However, long-term real-world evidence on visual outcomes from structured screening programmes remains limited. This study evaluates, in a retrospective analysis of routinely collected clinical data, the real-life visual outcomes of screening for and treating sight-threatening DR, based on 32 years of data collected in a purpose-built centre implementing the 1990 European Working Party recommendations for screening. Methods: Screening was performed by retinal photography between 1991 and 2022 in 18,161 patients (63,289 screening episodes). Diabetes specialists graded photographs, referring patients to ophthalmologists when needed. The 10-year trajectories of visual acuity (VA) were assessed in patients with different stages of retinopathy and macular involvement at first screening. Results: At first screening, two-thirds of patients had no DR, 15% had mild DR, and the remainder had referable DR or a non-assessable fundus. There was no difference by sex. Patients with more severe DR at first screening had lower VA, but this did not worsen over 10 years. Median VA in 514 patients treated with panretinal photocoagulation for pre-proliferative or proliferative DR changed from 0.10 logMAR (7-8/10) to 0.15 (6-8/10), 1874 ± 1252 days after treatment. In 823 patients photocoagulated for diabetic macular edema, median VA remained 0.10 logMAR (7-8/10) before treatment and 1998 ± 1288 days after treatment. Conclusions: Screening for sight-threatening DR using European Working Party recommendations was feasible in everyday practice and was associated with long-term preservation of visual acuity and a low incidence of severe visual loss.