Prescription glasses are allowed - both competitors are wearing them. Those lens can correct for short sightedness, astigmatism etc, but they’re the exact same lens you find in eyeglasses. I used to wear these - I bought the shooting glasses off the shelf (or rather our club got them in bulk for us), then to get the lens made, I went to the exact same optical store where I got my prescription glasses made and basically told them to just order one lens for my right eye.
What I meant by magnification was, you can’t put optics on it so it works like a 2x scope. So the lens can make stuff look less blurry but not make it look bigger.