Yeah but you get the same strain with positive lenses as you do from negative ones. As an example, I don’t get a prescription to use my friends telescope or to use my optical microscope. I just adjust the magnification until I can see the stuff I want in focus. Lenses are just lame telescopes or microscopes positive or negative. If you could adjust them …by swapping lenses at Walmart for example, I could find a minus pair for reading and another for driving. For driving all you need is a simplified version of the air balloon toy they use to measure your prescription. It would simply present an image set ad driving distance. Then you just swap a few lenses until you get it right.

That would leave the really important problems for the ophthalmologist. Like cataracts or retinal detachment.