IntroductionThe prospective, non-interventional OCEAN study examined the use of intravitreal ranibizumab injections for the treatment of diabetic macular oedema (DME) in a real-world setting in Germany.MethodsAdults with DME receiving ≥ 1 ranibizumab (0.5 mg) injections were recruited by 250 ophthalmologists. Best-corrected visual acuity (VA) testing, imaging and treatments were performed according to the investigators’ routine practice and documented over 24 months.ResultsThe full analysis set included 1226 participants. Mean baseline VA was 60.6 [95% CI: 59.7; 61.5] Early Treatment Diabetic Retinopathy Study letters. VA improved by ≥ 15 letters in 21.5% and 23.5% of the participants at 12 months and 24 months, respectively. They received a mean number of 4.42 [95% CI: 4.30; 4.54] injections in the first year and 5.52 [95% CI: 5.32; 5.73] injections over 24 months, which was markedly lower than in clinical trials. Only 33.4% of the participants received an upload with four initial monthly injections as recommended by the German ophthalmologic societies. Time-to-event analyses that account for missing data inherent to a non-interventional study design demonstrated that participants receiving ≥ 7 injections in the first year had a faster response, but the duration of the response was shorter compared to the subgroups receiving 1–3 and 4–6 injections. Serious adverse events were reported for 143/1250 (11.4%) participants in the safety population.ConclusionUnder-treatment is a major problem of DME anti- vascular endothelial growth factor therapy under real life conditions. Despite fewer injections given compared to randomised controlled trials with a consequently reduced overall mean visual gain, a profound functional improvement (≥ 15 letters) was achieved over 2 years in 23.5% of eyes with DME.Trial Registration NumberNCT02194803, ClinicalTrials.gov.FundingNovartis Pharma GmbH, Nuremberg, Germany.