I often joke that any technology that I enjoy is doomed to failure.  A case in point.

A little known fact is that an astronaut slowly loses visual acuity due to the bulge in the eye ball from lack of gravity.  NASA sponsored the development of eyeglasses that did not require lense grinding.  

I had worn bi focal eyeglasses for years and found them limiting.  I often had to observe mechanical systems overhead, which was not possible with current eyeglass technology.  My son, a Physical Therapist, said that falls due to bi focal caused distance misjudgment was a major cause of broken bones in the elderly.  So I became an early adopter of the Tru Focus brand of eyeglasses.

My glasses had a ground front lense due to astigmatism, held in place with small magnets.  The main lense was a circular gell sack that was stretched by a mechanical linkage.  The lenses could create focus from a few inches to infinity.  It was possible to adjust the focus at the top, middle, and bottom of a page of print.  Dust removal was an issue.  Wonderful technology that lacked a market.

A lower cost version is now being used to provide glasses to the world’s developing countries.  A syringe supplies gell to the lense, and is snapped off to cause a seal when corrected vision is obtained.