Originally funded with the help of DARPA / US Army, researchers in Switzerland have developed a "telescope" contact lens, which allows to switch between normal and telescopic view with a deliberate wink.
This technology was first published in 2013 and has since been improved. It is not ready for market yet.
But not only soldiers, but older people or people with visual impairments, who are mainly age-related (eg macular degeneration: https://en.wikipedia.org/wiki/Macular_degeneration) may look forward to it.
The lens currently zooms to 2.8 times normal strength and is turned on by the conscious wink with one eye and switched off with a wink of the other eye.
Currently, to activate the lens, a "wearable" be worn, or a 3D glasses, which makes things seem rather unattractive for everyday use.
Eric Tremblay of the École Polytechnique Fédérale de Lausanne is one of the main developers of this technology.
The development team hopes clinical trials will start until the end of the year, ...
details:
https://www.forbes.com/sites/meriameberboucha/2018/02/28/first-ever-switchable-telescopic-contact-lens/#1f7518f06ec4
https://www.newscientist.com/article/dn26968-telescopic-contact-lenses-let-you-zoom-in-on-demand/#.VOGwwPmsW4g