What does -4.25 in eyesight means

I have that too in my eye sight, its just what u can see it means that you are near sided that you can't see far away hope this helps

That is likely your distance prescription. There are other variables, usually. Peraps an astigmatism, bifocal, different vision in either eye.

How does your prescription read?

It probably means that without glasses objects are in focus at about 9.25 inches or less.

1/4.25 is the focal length in meters.