The Nakuru Eye Disease Cohort Study

Objective: To provide six-year cumulative incidence of visual impairment and blindness, diabetic retinopathy (DR), age related macular degeneration (AMD), visually impairing cataract and features of glaucoma in an older age Kenyan population and the risk factors for each. Design: Population based cohort study with six-year follow-up (n=2,171; 50% participation) Main outcome measures: Six-year cumulative incidence of visual impairment and blindness, DM, DR, AMD, visually impairing cataract and features of glaucoma, risk factors for incidence and population estimates. Results: The six-year cumulative incidence of visual impairment and blindness was 119.4 (103.1 - 137.9) and 15.1 (10.4 – 21.7) per 1000 of population respectively. The six-year cumulative incidence of DM and DR (in those with diabetes mellitus) was 61.0 (50.3 - 73.7) and 224.7 (116.9 - 388.2) per 1000 of population respectively. The six-year cumulative incidence of AMD was 164.2 (136.7 - 195.9) per 1000 of population and the six-year cumulative incidence of visually impairing cataract was 235.6 (213.5 – 259.3) per 1000 of population. Associations with incident cases were demonstrated for each with age and diabetes being the leading associations across the primary outcome measures. Conclusions: This six-year follow-up of a population-based cohort indicates a high incidence of visual impairment and blindness and provides data, for the first time, on the incidence of DR, AMD and cataract in Kenya. A large gap exists between provision and need for services and cataract control should remain the priority focus with work to strengthen health care systems as posterior segment eye diseases will become a greater issue as services improve and cataract comes under greater control.