I am more vision impaired than your wife, most likely. I cannot see the shopping list well either, and I sure as heck don't drive anymore.
Nevertheless, I am able to see the shopping list on iPhone just fine now, because I recently got a newer Plus size iPhone, and I know how to enlarge the screen display by spreading my thumb and index finger over the screen. It shows up well for me to easily read it.
Printing the shopping list has been discussed here before, and the take away is it is a lot of hassle.