Reduced prescription 20/40 - question

[Aquila]

I read on many books and sites that a reduced prescription to 20/40 is recommended, but it was never mentioned whether the prescription needs to be 20/40 vision for each eye (seeing 20/40 while only one eye is open) or 20/40 while both eyes are open (which means each eye see something like 20/50) ??

So which one is it ??

thanx in advance!

[Nancy]

20/40 with both eyes together, so you can drive safely. Get an eye chart if you don't have one so you can monitor your progress and know when these glasses are getting too strong, and move to a weaker pair, or none.