The physical exam form on the
Lethal Weapons Training page says at the bottom that your better eye must be at least 20/70 uncorrected and your other eye must be at least 20/200. The rest of it's a little wordy, so I could be wrong, but I'm thinking it means that, on top of the 20/70 and 20/200 requirement, you have to use glasses/contact if your vision is not 20/20 or 20/40.