@j23
Doctors who prescribe for presbyopia of course don't tell the patients to print push so of course there is limited by chance or no hyperopic defocus.
Yes, I now realized that for presbyopia a person is using glasses for the near point, thus this is the opposite for using the same glasses to extend the FAR point of the eyes. Only when accomodation range is nearly zero (for very old people) the conditions are the same.
So the summary would be (theoretically) - that when the far sight is 'emmetropic' then it prevents the eye to grow even if near point is shifting.
Do you mean rather
myopic defocus? (myopic defocus should force the eye to get shorter - while hyperopic defocus ask the eye to grow, of course only in theory as we know that the eye is not growing for those people to adjust). When a person cannot see near point it means there is a natural hyperopic defocus in central retina which PLUS glasses move a bit to correctly focus.
The same goes for tooth cavities. If you ask a dentist if teeth cavities can be reversed he/she will say no except from very early stages with Fluoride.
For your example maybe more appropriate is to compare to swallowing gums (then we have a reversible condition on 'elastic' tissues, and not a tooth which structure is rather tough).
