APR 16, 2010
This experimental study involving chicks suggests that the apparent protective effect against myopia afforded to children who spend more time outdoors can be explained, at least in part, by exposure to higher ambient illumination.
In the study, the chicks were fitted with translucent diffusers and divided into various groups, each with different exposures to natural or laboratory lighting. Researchers found that the removal of diffusers for 15 minutes per day under normal indoor light levels significantly retarded the development of myopia, and this effect was even stronger under high indoor light levels and stronger yet under direct sunlight.
The study's authors concluded that it is not necessarily the type of illumination - natural or unnatural - that matters in the protection against the development of myopia but rather the intensity of illumination, although it is still unclear exactly how illumination does this.