[Lewis Thomson (OP)]

Florian has been wondering about this situation and would like to know if science can help find answers.

"Can you train your eyes / your eye muscle to prevent becoming short-sighted/long-sighted due / loss of sharpness due to aging or even to recover keenness again?"

Leave your thoughts in the comments below...

[Petrochemicals]

Many people who have bad vision have already retrained their eyes to focus on something far too close to them, be it television or something else. I believe in most cases the eyes could be retrained, but the eyes would need to be retrained to try to achieve focus.

Computers mobile phones etc are having a bad effect.

[Origin]

I believe in most cases the eyes could be retrained, but the eyes would need to be retrained to try to achieve focus.

Is there any evidence to suggest this is true or is it just your belief?

[Petrochemicals]

I believe in most cases the eyes could be retrained, but the eyes would need to be retrained to try to achieve focus.

Is there any evidence to suggest this is true or is it just your belief?

Well, there is the sentence before the one you quoted. In the paragraph that you took the trouble to edit. But I suppose really it's just my ferverous need for attention that motivates me to make comments based on a post without my reply having any real substance.

[Origin]

But I suppose really it's just my ferverous need for attention that motivates me to make comments based on a post without my reply having any real substance.

Noted.

[Bored chemist]

Many people who have bad vision have already retrained their eyes to focus on something far too close to them, be it television or something else.

Is there any evidence to suggest this is true or is it just your belief?

[Janus]

Nearsightness is most commonly caused by one of two things: Too thick a cornea or an elongated eyeball. The result of either is to alter the "rest" focal point of the eye with respect to the retina. 
The eye focuses on objects by distorting the shape of the lens from its rest state, but there is a limit to the lens' flexibility, and the shift in the rest point, puts focusing on distant objects outside the lens' flexibility range.
This not something you can "train" your eye to overcome.
On top of that, you can have astigmatism.  This is caused by a mismatched curve in either the cornea or lens.  This prevents the eye from having a sharp focus point and, again, is not something you can train your eye to correct.

[evan_au]

Another factor to consider is that as we age, the lens gets stiffer and/or muscles get weaker, so we have a reduced ability to focus over a wide range. That's why older people often end up with bifocals.

[Janus]

Another factor to consider is that as we age, the lens gets stiffer and/or muscles get weaker, so we have a reduced ability to focus over a wide range. That's why older people often end up with bifocals.

Or, like in my case, since I was already near-sighted, start looking over the top of your glasses when looking at things close up.( since my glasses were shifting the focus point further away, not using them meant it reverted to its "natural" closer point.
I did that for awhile, before finally getting bifocals, and I still do it if I have to shift back and forth between something on my desk and the computer screen. Glasses for desk, over the top of them for computer screen. (it beats constantly tipping my head up and down)

[kevinvholloman]

Nearsightness is most commonly caused by one of two things: Too thick a cornea or an elongated eyeball. The result of either is to alter the "rest" focal point of the eye with respect to the retina. 
The eye focuses on objects by distorting the shape of the lens from its rest state, but there is a limit to the lens' flexibility, and the shift in the rest point, puts focusing on distant objects outside the lens' flexibility range.
This not something you can "train" your eye to overcome.
On top of that, you can have astigmatism.  This is caused by a mismatched curve in either the cornea or lens.  This prevents the eye from having a sharp focus point and, again, is not something you can train your eye to correct.

Totally agree with you. But there is a physiological ability of the body to correct slightly myopia once in a lifetime. I will try to explain: Many doctors believe that ideal vision for a person is 90-80% of the norm (I don’t know how to spell it correctly). This is the percentage that allows you to see well throughout your life and do without glasses. As a rule, when a person turns 40-45 years old, some changes occur in the body, they also occur in the structure of the eye. Almost all people develop physiological farsightedness at this time, and if we consider vision as a percentage, then there is an "improvement" of vision by + 10%. A person at this time begins to see better objects that are far away and worse objects that are close (forced to wear reading glasses, such as newspapers). If a person has had myopia all his life (an insignificant 90-80% of the norm), then during this period he continues to see just as well, that is, he does not need reading glasses. It turns out in this case, vision is restored a little.

[evan_au]

The main training is to ensure that children go outside for a while every day, in bright sunlight (ie take some time off from screens).

the norm (I don’t know how to spell it correctly)

Are you talking about a lens prescription of +1 dioptres or -2 dioptres?

See: https://en.wikipedia.org/wiki/Dioptre

[Tsm3696Monkey]

I'm working at the laptop all day, and it hurts my eyes so much. I'm thinking about buying special glasses for it.

[vhfpmr]

Many people who have bad vision have already retrained their eyes to focus on something far too close to them, be it television or something else. I believe in most cases the eyes could be retrained, but the eyes would need to be retrained to try to achieve focus.

Computers mobile phones etc are having a bad effect.

Good luck with that one, leaving poor eyesight untreated increases the risk of dementia.

https://academic.oup.com/aje/article/171/6/728/114039?login=false
https://www.karger.com/Article/Abstract/52814
https://agsjournals.onlinelibrary.wiley.com/doi/abs/10.1111/j.1532-5415.2004.52554.x
https://agsjournals.onlinelibrary.wiley.com/doi/abs/10.1111/j.1532-5415.2005.53219.x