BBC Reporter James Gallagher sent us this special report on how it works.
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Sight-saving 'eye' phone app

15 August 2013 Last updated at 08:26 BST

Scientists in London have come up with a way to use a mobile phone app to check people's eyesight.

It could mean people in remote parts of the world getting vital help they would otherwise miss out on.

BBC Reporter James Gallagher explains how it works.