There are a few things you should consider. First, are the opt schools you are interested in research-heavy schools (SCO is mostly clinical, not a whole lot of research is done here)? Also, are you interested in doing research after optometry school? If so, it may be beneficial to you to get some research experience. If not, and you don't plan on going to a research school, research isn't really necessary. Definitely don't waste your time doing research if you don't want to, just because you think you have to for your app. On the other hand, if you find a project that really interests you, go for it!