Half the world will be short sighted by 2050, says Brien Holden of the Brien Holden Vision Institute, Sydney, Australia, mostly because of lifestyle changes, and staring at computer screens all day long. That’s an eight-fold increase in the number of people with myopia, in just a few decades.

The study looked at 145 studies covering 2.1 million participants, dating back to 1995. This meta-analysis allowed them to estimate future trends. The results showed an estimated 1.4 billion people (23% of the population) with myopia in 2000, which will rise to 4.8 billion in 2050 (50%).

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Why is our vision getting worse? The increases in myopia “are widely considered to be driven by environmental factors (nurture), principally lifestyle changes resulting from a combination of decreased time outdoors and increased near work activities.” That is, staring at screens, working indoors, and squinting at tiny stitches or solder joints on factory lines are all weakening our distance vision.

The study further predicts that myopia will become the leading cause of vision loss by 2050, with a sevenfold increase in pathological myopia, making it the leading cause of permanent blindness.

Those are scary numbers, but these changes will be expensive, too. In 2010, “The economic burden of uncorrected distance refractive error, largely caused by myopia, was estimated to be US$202 billion per annum,” says the report, a figure set to rise as fast as our eyes degrade.

The authors note that their figures don’t take into account any corrective action. This is a worse-case scenario, and will only occur if nothing is done to prevent it. For you and I, this isn’t really a problem. We already visit our opticians, and we have corrective aids and surgery readily available. But for poorer people, or folks in developing countries, it looks like a major potential issue, and just one more case of our modern lifestyles destroying our bodies, even as medicine extends our lives.