Pepper spray into eyes will cause a lot pain in the eyes. Just a little spray could make your pain in eyes last for a few minutes. A large quantity of pepper spray could cause strong pain in eyes which will last as long as one hour. If it is very serious, it can cause temporary blindness. The only thing you could do is wash the pepper spray out with running water immediately, but the pain and burning feeling will continue. You can try to put some ice on eyes to relieve the pain and burning. Even you feel the pain and burning is gone, you'd better let your eyes have a rest. If you keeps feeling the pain and burn, your eyes are swelling or develops chest pains, a cold sweat, pillow breathing or fever, which make you feel awful, go to the hospital immediately.