https://www.engineeringforchange.org/solutions/product/adspecs/

Hopefully if enough of these get distributed it won't be so much of a problem except for people with astigmatism.

https://www.epo.org/en/news-events/european-inventor-award/meet-the-finalists/joshua-silver

Joshua Silver, a professor of physics at the University of Oxford, first had the idea to manufacture adjustable lenses for the poor, removing the need for expensive equipment and professionals, in May 1985 after he had created a variable focus lens out of curiosity.

His invention allows wearers to adjust the glasses to their personal prescription without the assistance of a healthcare professional. They simply look at a reading chart and adjust the glasses until they can see the letters clearly.

The glasses use durable but flexible plastic lenses, which have fluid sacs filled with silicone oil between them. These glasses can easily be adjusted by the wearer by simply adding or removing some of the oil in the sacs.

The invention is not without its limitations, however. Currently, the principle only functions successfully with circular lenses, limiting the design opportunities. Additionally, the principle can only alter the magnification of objects, so the glasses cannot treat those with astigmatism. What these spectacles lack in aesthetics, however, they make up for in spades with utility and work on non-round lenses is already underway.

His stated goal was to make the overall cost of a pair of glasses as low as $19.