Size of text in the new Retina MacBook Pros
As you can see on the new MacBook Pro page (under the Retina-feature item), if you use the binoculars on the text, it doesn't look smaller. It just looks much, much, much sharper! 

It's the same as the iPhone 4(S) comparing to the iPhone 3G(S). You don't need better glasses to read the text, because it's not smaller. It's just much sharper and easier to read.

Maybe, I can make my point even better with the iPad Retina page. You'll see you can fit as much text on both the Retina screen as the normal screen. It's just sharper!

Before you make a comment, YES, I know it's a screenshot of an iPad and the question is about the new MacBook Pro, but I didn't found any image with this much text on the new MacBook Pro, so hence the iPad Retina screen.