Please have a vet out. One of my horses has recurrent Uveitis- also known as moonblindness. The first signs are weepy eyes, horse is squinting and has puffy eyes and red blood vessels in the sclera and in the lids. This is really a serious disease. Its not a typical "eye infection" where it has green or yellow pus, it will make the horse blind eventually if it isn't treated. When my horse's eyes flare up, I have to give him atropine drops and he gets steroid shots. He has to wear a fly mask 24/7 because the light hurts his eyes.
Spent a whole hour today laying in a pasture, waiting for a sparkling vampire to show up. Alas, I woke up and looked over, only to find a mound of horse crap. Sigh.