Can you use concealer as an eye primer?

You can! :] Primer is just a base so that your eye shadow or powder will stay longer. It's very helpful if you're not using straight pigments and just cheap eye shadows. If you have sensitive eyes be careful not to get your concealer or base in your eyes because that will be painful and can cause a sty. I use Almay cover stick (looks like skin colored lipstick) as my eye concealer, but it's really just whatever works for you and can work with your budget.