Refractive error (e.g. myopia) is an important public health concern worldwide, as the most common cause of impaired vision. There is increasing interest in the affect of social position on visual health, considering the whole range of severity including those with mild impairment. ALSPAC is included in our programme of work within CLOSER (Cohort & Longitudinal Studies Enhancement Resource) which is investigating visual function and refractive error, making comparisons both within and across UK-based cohort and longitudinal studies. We will apply life course epidemiological approaches to investigate biological, environmental and lifestyle factors influencing the development of refractive error and the biological and social factors that influence visual health. We will also investigate the health and social outcomes associated with impaired visual health and with refractive error. Using several studies, which started recruitment at different times, we will assess any changes over time in both risk factors and outcomes which may help to identify modifiable risk factors.