Today was a university wide open day so I was helping out by taking prospective students round the building, showing them where Doctor Who and Sherlock were filmed (see here for Dr Who); answering questions; using a slit lamp and demonstrating simulation spectacles which simulate the wearer having various optical conditions like glaucoma or cataracts.
Optometry tends to be a lesser known subject and because we are little away from the main campus we don't get a massive number of people but it does mean that the ones we do get are generally interested in the subject or at the very least thinking about it. Prospective student open days are a little different from offer open days in that you need to convince the student that optometry is the career and course for them rather than convincing them that Cardiff is the best place to study the subject. This requires a slightly different approach but the main similarity is to just be friendly and talk to everyone. If you can't do that then optometry possibly the subject for you anyway.
I always enjoy helping out with open days as I know I didn't know what I wanted to do the first time I went to university. Having a look at different options and seeing what people think of the course and whether you could see yourself in their shoes is a great help in my opinion.