Often, you might wonder why a lot of emmetropes and hyperopes do not become myopic over time.
This one is actually pretty simple…
For the same reasons that not all myopes become more myopic over time!
So, the question is really more about what helps vision stay stable.
Here are just a few ideas. Feel free to add more to this thread…this and is a group effort but I’ll start you off.
Some emmetropes are between 0.0 and -0.50 D. These people see slight myopic blur at far distances, which might protect them according to some studies.
Emmetropes between 0.0 and +0.50 D may occasionally see myopic blur due to normal use of accommodation, and especially after sustained close work.
Emmetropes in #2 on the plus end who wear glasses at times for close work definitely see myopic blur through them at times, which may be protective. (Just as some emmetropes on the negative refractive end wear distance glasses on occasion, some on the plus side (without presbyopia) wear plus glasses for sustained close work (similar to differentials), due to their mild farsightedness making sustained close work more tiring.)
The adult human eye seems fairly resistant to dramatic refractive change (multiple diopters per year) under steady-state conditions, but if anything seems to tend toward changing in the plus direction after age 50 or so.
Just not wearing minus means no lens induced myopia.
And there are tons of other ideas…feel free to add more below.