Croc, +40's eyes are usually just fine. There's nothing that can be "fixed", and there'll still be a problem with small fonts. The focus range decreases, and it's common to end up with a range that cannot possibly be "fixed" by multifocals or anything, because no multifocals can successfully reduce the closest focus distance while at the same time keep the horizon focus distance. Not without creating horrible multifocals with way too small sharp regions. Multifocals will normally allow you to focus down to about 30cm or so, not much shorter. At best.

As the screen size cannot reasonably be increased in something that's supposed to be a phone, the only fix is to make it easy to adjust font size (and add good, working reflowing features in browsers and the like).