I often find the conclusions made by scientists to be rather amusing. A researcher in Australia that is doing otherwise solid work has been paraphrased as having stated that exposure to bright light counteracts myopia. While there is certainly evidence that environmental factors have a strong impact on visual development, this conclusion doesn’t seem to consider the mechanics at work in the eye.
The issues at play in myopia are the shape of the eyeball and the ability of the lens to change shape to provide a wide range of focus. How are the activities of the iris blocking light or retinal stimulation supposed to affect these characteristics? Doesn’t it make more sense that the muscle fibers of the lens will optimize themselves to match the activity that they undergo early in life. If a child stays in an enclosed environment all of the time, there is no opportunity to use long range focus. Likewise, when a child pends all of their time outdoors and never reads or uses a computer, there is little opportunity to exercise short range focus. Presuming that there is a reasonably regular distribution of behavior in any given population, this suggests that there would be a higher prevalence of hyperopia (farsightedness) in places where there is a low incidence of myopia.
I haven’t extensively read the man’s work, so I don’t fully know his position, but it is curious that more obvious features about being outdoors were not mentioned in the article. However, it wouldn’t surprise me if he really thinks this. There is a shocking lack of ability to envision systems within the scientific community.