Correction CANNOT give you 100% perfect vision- it can only improve your vision.....
Obviously everybody's eyes are different but somebody with say +5.5 Could be corrected but may not be corrected up to +0.0... they may still have a residual prescription perhaps of +1.75 forexemple.... this fact would therefore mean that you could not achieve 100% 20/20 vision......
Also there is only so much you can correct - You've seen people with "JAM JAR" bottom glasses haven't you? The correction in this is immense yet their vision may still NOT be 100%
There is technology available to get the same prescription into THINNER lenses.... however it has its limits and you can only refract up to a certain point...
Hope this makes some sense.
JON