"If you can read this..." makes no sense

It says 'If you can read this, you don't need glasses' in the opening scroll, but what kind of sense does that make?

First of all, what if you are WEARING glasses while reading it, and thus can read it just fine? You still don't need glasses?

Second of all, shouldn't it AT LEAST say 'If you can read this WITHOUT glasses, you don't need glasses'?

Third of all, it's a movie, so you can basically figuratively glue your eyeballs to the screen/monitor/TV and read any text that's legible with or without glasses, so what does that prove?

Fourth of all, people that need glasses, that are not wearing them, can still read text using 'tricks' - one individual taught me how he can read things he can't REALLY see, because of the 'shapes' and 'length' of the words, and how they tie in together, so they can 'estimate-read' things they can't properly see. Do THOSE people not need glasses?

I mean, they CAN read it, just not SEE it properly. Why wouldn't they need glasses?

The whole 'joke' makes NO sense, unless you are a 'two-eyes' and simply bypass any logic and ignore any struggle glasses-wearers have to go through. "Hehe, I can read it, so I don't need glasses, how funny!"

NOT.