I don't think it matters...there's also a section for "optometric experience" and the only thing I had to put in there was being part of a pre-optometry club. No one asked me a single thing about that...so I really wouldn't worry. I think they want to give people the opportunity to put something if they have done it. Plus that is how some people show what they were doing with their time. Like I always took a class load less than 15 credits because I worked a lot through college. So it wasn't that I was being lazy - I was able to show that I really was filling my time. As long as you can show that you have really filled your time up with things, then that's all they will care about. They want to see that you can handle having lots to do at once, because that's what school will be like.
If you can get a summer job as a tech at an optometry office, that would just be a bonus!