There'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's a notching tool which notches the lens so it'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.
This was developed in India decades ago, but I can't find those kits online. Obsolete?
This was developed in India decades ago, but I can't find those kits online. Obsolete?