I don't know if the type I got once are the same sort, but either way, I once had to get some special eyedrops when an eye doctor was examining my eye. My cornea had been scratched a few days before when my brother accidentally kicked me in the eye; a couple days after the injury I couldn't open either eye -- yes, the pain was that bad. Once I got those eyedrops, though -- the pain was gone. At least, temporarily.