Pontacain (spl?) was the most widely used several years ago but I have been told there is another drug more popular today, not sure on that one but Pontacain Hydrochloride stops the pain instantly! It was for years that a lot of shops kept the stuff in the first-aid kit and although it was not an over-the-counter drug it was fairly easy to get, in some cases all a person had to do was sign for it at the drug store. About 20 years ago I tried to renew my supply at the shop and was told by the druggist that he could no longer let me have it without a written doctors prescription. When I called my doctor he told me they had cracked down on it and he could not let me have it unless it was for a case he personally examined, he also told me it was a very bad idea to keep the stuff on hand because people with serious eye injuries were using it instead of going to the doctor and were, as he put it, going blind with a smile on their face! The point is if you need something as strong as that then you really don't need to be treating it yourself anyway and although the vast majority of "flash burns" are not going to be dangerous the small percentage that could be that serious is not worth the risk. If those eyes are hurting enough to need something like Pontacain Hydrochloride for relief then a person really needs to see his doctor while he can still see anything!
Your eyes are to precious to treat a serious injury yourself and without seeing a doctor you don't know how serious that burn may be. Don't risk it, it's just not worth it!