Maybe I can rid myself of these infernal tri-focals.
I think you would find that constantly fiddling with the manual focus adjustment a lot more onerous than just tilting your head slightly (FWIW, I wear tri-focals too). It sounds cute on paper, but I doubt the practicality of it in the real world.
What might be nice would be clip-ons that “decorrect” for those aging viewers whose far-vision prescription is too powerful to allow them to read comfortably. If you play a musical instrument while reading from a score, it helps to be able to have the entire field of view in appropriate focus for the score.
What is needed now is a little chip about the size of a flea that watches your eye and automagically adapts the lenses to whatever your eye seems to be straining to adjust to.
There would, of course, be a version where the hysterisis on the circuit is set wrong, a plane crashes and billion dollar lawsuits occur.
Pretty set path for product development these days. My grandkids won't have to worry about their vision.
/johnny
I concur. I have continuously variable focus, with the little hour glass zone. I had lens implants a few years ago due to cataracts, so my farsightedness is absolute. ( Before that I had extreme myopia, so it was quite a change. ) I had bifocals before, and I adjusted instantly to these new glasses, quite literally. I was very pleased from the moment I tried them on, and I would have no interest in any kind of manual adjustment.
BTW, these lens implants are a tremendous boon, as my far vision is very sharp, being limited only by the age of my retinas and a modicum of “floaters”.
If the lens is mechanically adjustable, it should be adjustable by electronic means also.
A circuit could be set up to contantly adjust it for the correct setting to whatever the lens is ‘looking’ at/