Dependency between light intensity and refractive development under light–dark cycles

The Influence of Light Exposure and Seasonal Changes on Short-Term and Longer-Term Changes in Axial Length of the Human Eye

“…We found that the axial elongation was slower by 0.002 mm/year for every minute spent in bright outdoor (>1000 lux) light in this population of university students. Our findings are consistent with a previous longitudinal study of children which showed that greater light exposure is associated with slower eye growth , and with previous animal studies reporting an association between eye growth and ambient light levels (Cohen et al, 2011). The findings also support the widely reported finding from studies on children that time spent outdoors is protective against myopia development, but In these young adults, the 6-monthly seasonal changes in axial length and daily bright light exposure were also demonstrated to have a significant inverse association.…”

“…Therefore, our study supports the notion that environmental risk factors such as light exposure also appear to play an important role in refractive error development in young adults. Our study findings, together with animal studies showing that bright light exposure can protect against the development of myopia (Ashby & Schaeffel, 2010;Cohen et al, 2011), support the potential for interventions such as increasing time outdoors that have demonstrated efficacy in reducing myopia development in children (Wu et al, 2013;He et al, 2015) to also impact on myopia development and progression in young adults.…”

“…A recent study showed that chicks raised under low illuminance levels of 50 lux (while maintaining the normal light/dark cycle) develop significant myopia, whereas those raised with elevated light levels of 10,000 lux develop hyperopia. This study also revealed that chicks raised under an intermediate illuminance level of 500 lux emmetropized normally (developed minimal refractive error) (Cohen et al, 2011).…”

“…Although an association between light exposure and eye growth has been documented in young adults in our current study, as well as in children and in animal models of refractive error development (Ashby et al, 2009;Ashby & Schaeffel, 2010;Cohen et al, 2011;Smith et al, 2012;Smith et al, 2013), the mechanism underlying this association is unclear. A mechanism linking light exposure and eye growth involving retinal dopamine (a light sensitive neurotransmitter) has been proposed based on evidence from animal research.…”

“…These findings suggest that a sampling duration of at least a week and a sampling frequency of There is wide ranging evidence from both animal and human studies, supporting an important role for ambient light exposure in the regulation of eye growth and the development of refractive errors. Animal research demonstrates that the normal rate of eye growth and refractive development can be influenced by the level of daily ambient light exposure (Cohen et al, 2011), and that exposure to elevated light levels can inhibit or slow the development of experimental myopia (Ashby et al, 2009;Ashby & Schaeffel, 2010).…”