Long periods reading is associated with a greater risk of myopia.

Scimex: A major study has revealed that more than four out of five Chinese students suffer from myopia and researchers warn Australia could see similar rates of short sightedness in the future. "There are many factors that appear to influence the likelihood of a child developing myopia," Professor Wang from Edith Cowan University said. "Spending long periods reading material that is within 30cm of the readers' face is associated with a greater risk of myopia.

"Conversely, spending time outside and taking regular breaks from reading or studying seem to reduce the chances of developing myopia."
Researchers interviewed 4677 students in Year 10 and 11 from Beijing and found that 80.7 per cent suffered from myopia.
Prevalence and associated factors of myopia in high-school students in Beijing was recently published in PLOS ONE.
Professor Wang said that while the rate of myopia in Australian students was significantly lower, many of the factors behind the high rates in China are also present here.
"As students spend more time studying and reading and less time outside it is likely that we could start to see rates of myopia in Australia approach those seen in China," he said.
Optometry WA President and owner of EyeQ Optometrists Darrell Baker said that while the rates of myopia are much lower in Australia, he had noticed a rise in the number of younger people  with short sightedness.
"When I started in 1987 if we had a young adult  come in to get tested we would reassure  them that their eyesight was unlikely to change significantly  until they got much older," he said.
"Now it's not uncommon see young adults developing myopia , and teenagers with higher rates and severity of myopia , so this anecdotal evidence  tells me that it's most likely environmental factors playing a  part."