Ever since I started using computer back in 1982, with my first Apple ][ Bell & Howell Edition, I have needed to wear glasses. Staring for hours at tiny screens didn't help matters and I've worn prescription lenses ever since. It's just a necessary evil, with my job requiring so much computer interaction. However, Scientific American tells us about future phones that could do the vision correction on their own, allowing users to view the screen without glasses.
Such an advancement could be ideal for folks who need glasses just for looking at such a display. Typically that's for farsighted users who can see long distances just fine but need corrective lenses for up-close content such as you'd find on a GPS or smartphone. I've tried something similar, not with Google Glass but with a competitor, Vuzix. They make a set of glasses that has adjustments so I can see their virtual screen, in focus, without using my own prescription lenses.
This type of technology makes sense for a personal device, such as wearables and GPS devices. A tablet or laptop might not be ideal, as multiple users might be looking at the same screen, at times, although facial recognition could help and detect if the person who is using the device is known to need corrective lenses. The device might even detect if they have their glasses on or not, or if they are squinting or holding the device far away to get a better view. One thing is for sure; it's an exciting time for those of us who need glasses to use our smart devices!