Optometry schools want to make sure you know about the profession that is why most (could be all) of them want you to have shadowing experience (Non paid shadowing of an Optometrist). I would try to shadow a couple different types of settings, if possible, as well
I know in the interviews I had, they asked me about Volunteer work. I don't believe they look too deep into the specific type of volunteer work but they would like to see that you give back to your community. For example, my volunteer work consisted of coaching a kids baseball team!