Advice please?

I have myopia in one eye which I think is steadily getting worse. It doesn't affect my vision but I just worry about something happening (eg. couldn't get my damn learners permit because I had to read the letters off the board with one eye closed and I couldn't see anything with my bad eye!). My optometrist says that because it's not affecting my stereoscopic vision I don't need gles. Should I get a second opinion?