Question

If you wear contact lenses, why should you remove them while you are in the laboratory?

Answer 1

This is a standard rule in any lab that I know of. If you get chemicals in your eyes while wearing contacts, the chemicals can cause your contacts to fuse to your eye, which could (more than likely) cause blindness. Even though you may not be using chemicals in a basic physics lab, there is still a small chance of something getting into your eye, and if you're wearing contacts, it can make it difficult to wash off your eye. Hence why you should also wear goggles.

Answer 2

What we have been told is that even the vapours of some volatile compounds can be harmful for your eyes. The gas might be caught in the space between your eye and the contact lens and stay trapped for a long time. Honestly, I find the latter explanation a bit weird as surface tension would try to stick the lens and the eyeball together but it was a professor in chemistry who said it, so I assume it's true.