This is just a curious observation. I found it a bit humorous that you mentioned you were visually impaired but your font size in your post was smaller than normal.
That wasn't a joke about your impairment. I myself am starting to suffer from age affects to my eyesight but it was odd to me.
Anyway I hope someone is able to help you so you can enjoy the game easier.
Edit: I should have also asked, is it all text in game you were hoping to enlarge or were there just specific parts you found hard to see?