What do I do?

Alright, so I have strabismus. I'm an early teen. To treat it, I use bifocals. I also am ver nearsighted, I can hardly see a foot in front of me. I need stronger glasses, I can't see the board at school. In order to see I have to flip my glasses around an close the other eye because one side is stronger than the other. The parts the help with my nearsightedness cancels out the bifocals, however, which can cause my eye to permanently turn in and I'd have to get surgery. The doctor prefers to have as little prescription as possible. I've worn glasses since 1st or 2nd grade, and I'm in 7th grade now. I went through like 4 pairs of glasses last year because they were getting worse (nearsighted wise, no strabismus) every few months and I needed new glasses often. I need them again. I've brought it up with my parents and they said they've gone over the options and I just have to deal with the fact I'm not going to have perfect vision. It really is annoying me, but I don't know what to do because if I get stronger glasses it's like 350 dollars or more and it risks my strabismus getting worse and if I don't I won't be able to see. I can't see people's faces as they walk by so I don't know who they are and I'm not supposed to flip my glasses around because for some reason they think ill break my glasses by doing that although my eye doctor says it's smart. What should I do? I'm sure my parents would let me if they knew I needed it, and one eye keeps getting worse. Help?