i think thier may be alot of misunderstanding of how eyes works. it seems everyone has a knowing and opinion on how the eye works, yet people are still barely able to cure these problems.
First off If your nearsighted, verify with your doctor and you can look on a video camera to verify, that your eyes are slightly crossed.
I believe the reason people can focus has little to do with the shape of thier eyes and more to do with how they move them.
What i would like you to do for me is to look at something you are having a problem with looking at it.
Now I want you to close one eye and see if your vision improves.
Basicaly the reason people dont see double is because they constantly move thier eyes.
When you focus on the wall with your finger in front of you, you should see 2 fingers and if your reading something what you are reading will be double, blurry and out of focus.
Now i want you to focus on your finger in front of you, noticing in order to do so, your actually crossing your eyes the closer and more middle your finger gets.
So the answer to your problem, may be simply to wear an eyepatch when doing reading.
If you have problems like stingy vision, etc teary eyes, then this may be a sign you need eye surgery.
This technique will take away double vision out of both nearsighted and farsighted people.
If you ask your doctor to check his patients, farsighted people are having problems crossing thier eyes.
We have to cross our eyes to keep from doubling objects close to us, while the background image doubles.
Nearsighted is the reverse, people with nearsightedness as reading books to much, etc. people who are nearsighted i believe
have thier eyes slightly crossed from
looking at something close.
This is why some excersizes cure the problem.
Also try holding what your reading out about 2 feet in front of you so you dont cross your eyes and give yourself eyestrain.