I'm over 40 and already have reading glasses,
Similar for me, but I am finding my first pair of bi-focals to be a bit of a WOMBAT, and will probably revert to separate distance and reading glasses on the next iteration.
but I'd need to get special phone-only glasses to see any more detail or smaller type.
I got a 7in tablet instead. Surfing on a phone needs both magnifying glasses (a binocular microscope, or jeweller's hands-free binocular loupe ; I use both routinely) and probes to activate the touch screen.
It must be almost heretical to some of the younger developers to hear mantras such as "smaller is better" shrugged off as self evidently stupid. Oh dear. What a pity. Never mind.