@Jennythelib - Does your mother know how she picked it up? Did you maybe have an indoor-outdoor cat? My understanding is that cats who stay strictly inside very rarely contract toxoplasmosis, because cats get it from eating raw meat - i.e., birds and rodents and other things much more likely to be found outside.
My grandmother had a nasty bout with toxo as an adult, when her kids were little - perhaps she was just very run down, as she had no particular reason to have a compromised immune system. Like yours, hers attacked the eye. In fact, she was left legally blind in one eye. She's managed quite well over the years. What I can't figure out is how she gets her eye makeup on!