Eric Greenwell schrieb:

Naturally, I made a measurement in the sun (UVI = 8), then another one
inside the cockpit (UVI = 0), indicating the canopy provides quite a bit
of protection. Testing other kinds of plastic, like baggies, plastic
wrap, Lexan, etc., gave readings from 0 to 7, so not every kind of
plastic is protective.

This is the reason why you needn't care too much about your sunglasses:
In the old days of glass glasses, it was the coating which protected
your eyes. There were good and bad coatings. Nowadays, it's the plastic
itself which protects. Get some cheapo poly-whatever, and your eyes are
protected, even with total clear glasses. Colour filter and sex appeal
may be a different story.

Stefan