Ocular and environmental factors associated with eye growth in childhood

Recent advances in measurement technology have improved our ability to quantify a range of ocular components and some environmental exposures that are relevant to myopia. In particular, environmental sensors now allow the dense sampling of personal ambient light exposure data, and advances in ocular imaging, such as developments in optical coherence tomography (OCT), enables high resolution measures of the choroid to be captured in human subjects. The detailed, objective information produced by these non-invasive measurement technologies has the potential to provide important new insights into the complex array of factors underlying eye growth, and myopia development and progression in childhood. Wearable light sensors and enhanced depth imaging OCT were both employed in a recently completed prospective, observational longitudinal study examining factors associated with eye growth in myopic and non-myopic children. Personal light exposure, choroidal thickness and axial eye growth were quantified in 101 children over an 18 month period. A significant association was found between objectively measured personal daily ambient light exposure and eye growth (independent of refractive status), consistent with greater light exposure protecting against rapid growth of the eye in childhood. Variations in the thickness of the choroid also appeared to be closely linked to the growth of the eye, with choroidal thinning typically being associated with more rapid eye growth, and choroidal thickening with a slowing of eye growth in childhood. The implications of these findings for our understanding of human eye growth regulation, along with their potential importance for our understanding of myopia control interventions, are discussed