In parts of South east Asia (e.g. Taiwan and Singapore) the incidence of myopia is currently 80% in secondary age students with many children beginning to show myopia at earlier ages (from age 5 and 6).
In Australia the incidence of myopia is far less-about 15% of the population and more commonly myopia starts around puberty.
Genetics and lifestyle
Myopia has a genetic predisposition but even more so myopia is linked to lifestyle and environment.
Recent studies have shown that time outdoors in some outdoor sport or leisure activity-has a strong protective effect against myopia (it was recommended that one hour per day be spent outdoors). So farming communities have significantly less myopia than do urbanised communities where there is also a greater time spent indoors studying and using the computer or watching TV.
So…the common sense conclusions are spend time outside each day playing and relaxing. Study and watch TV in moderation and try to include active leisure breaks outdoors rather than simply transferring from a study book to the computer chat line.