A new study projects half the world's population (nearly 5 billion people) will be short-sighted (myopic) by 2050.

What’s more, up to one-fifth of them (1 billion) will face significantly increased risks of blindness, if current trends continue, according to the study published in the journal Ophthalmology.

That would be a seven-fold increase in the number of people with vision loss from high myopia from 2000 to 2050, with myopia to become a leading cause of permanent blindness worldwide.

The rapid increase in the prevalence of myopia globally is attributed to, "environmental factors (nurture), principally lifestyle changes resulting from a combination of decreased time outdoors and increased near work activities, among other factors," say researchers from Brien Holden Vision Institute, University of New South Wales Australia, and Singapore Eye Research Institute.

The authors suggest the findings underscore the need for greater comprehensive eye care services and the development of treatments to control the progression of myopia and prevent people from becoming blind.

"We also need to ensure our children receive a regular eye examination from an optometrist or ophthalmologist, preferably each year, so that preventative strategies can be employed if they are at risk," said Kovin Naidoo, CEO of Brien Holden Vision Institute. "These strategies may include increased time outdoors and reduced time spent on near based activities including electronic devices that require constant focusing up close.

"Furthermore there are other options such as specially designed spectacle lenses and contact lenses or drug interventions but increased investment in research is needed to improve the efficacy and access of such interventions."