Age-related Macular Degeneration – 8-year incidence and progression in a population living north of the Arctic Circle

Abstract Objectives : Estimate the 8-year incidence and progression of age-related macular degeneration in an elderly Caucasian population living north of the Arctic Circle. Methods : This population-based cohort study included 2806 participants from the Tromsø Eye Study. Participants ≥ 55 years at baseline examination in 2007-08, who were re-examined in 2015-16, and had gradable digital colour fundus photographs (CFP) from at least one eye at both time points were included. CFP was graded for the most severe phenotype based on drusen size, geographic atrophy (GA), and neovascular AMD (nvAMD). Participants were asked if they had received treatment for AMD. Positive answers were validated by medical records. We calculated incidence based on the grading of CFP alone and combined with information about treatment for nvAMD. Results: The overall incidence of late AMD (GA and nvAMD) was 2.0 per 1000 person-years, with an 8-year cumulative incidence of 1.6 %. Information about anti-VEGF therapy did not change this estimate. The incidence increased with age, reaching maximum of 8.1 per 1000 person-years for participants aged 75-79 years. Incident late AMD was strongly associated with drusen size at baseline; 32.2% of the participants aged 75-79 years with large drusen at baseline developed late AMD. The 8-year cumulative incidence for progression to a more severe AMD grade was 30.9 %. Conclusions: The incidence of late AMD in a population living north of the Arctic Circle is comparable to other populations with European ancestry. Older age and large drusen are associated with an increased risk of developing late AMD.