Cheap technology for making optic lenses that could help 2.5B people and NASA
There&#x27;s been a practical solution to this problem for years - standard round lenses. Spectacles have three parameters - spherical radius, cylindrical radius, and axis. For round lenses, axis is set by mounting in the frame. There&#x27;s a notching tool which notches the lens so it&#x27;s retained in the frame at a fixed angle. So you only need a set of a few hundred standard plastic lenses, which fits in a small suitcase.<p>This was developed in India decades ago, but I can&#x27;t find those kits online. Obsolete?