I think some of the most acidic and harmful substances are sulfuric acid and hydrochloric acid.  Ammonia and bleach are also highly corrosive.  However, the average human body contains more acids than any of these substances.
assistant
Can I just ask what's a big part of what you're trying to figure out here? Are you trying to figure out if some foods are harmful to the eyes? Or something about acidity in general?
assistant
I know lots of foods are acids and some alkalines but I don't know which ones would do the most harm if they got in to someone's eyes.
user