I talked to my dad on the phone and he said I might want to go to the doctor, because if pink eye is left untreated in cattle, they can sometimes go blind.
(Of course I went to the doctor after that. Viral conjunctivitis does heal on its own. They can give you antibiotic eyedrops if you have bacterial conjunctivitis. The eyedrops felt like I was pouring lemon juice in my eyes. But hey, I could see!)
But for cattle, pink eye is a lot more serious. It also looks bad, poor things. As a result, we vaccinate our cattle for it.
Today we gave the dairy cows their pink eye vaccination shots. When cattle are outside there are flies in the grass, and they can spread it between cattle. (It can spread anyway, but the flies don't help matters.) We also vaccinated the heifers for it right before they went out to pasture.
If it were a choice between getting a shot and putting those drops in my eyes, I'd pick the injection every time.