I myself have tried some in my eyes by diluting into eye drop solution, what I tried was about 1 drop in maybe a tablespoon of the saline eye solution (what I had was Lugol's 5%, so really needed diluted). It definitely stings, but did me no harm. I used one of those individual eye solution droppers (the ones that have just one time usage), squeezed out all the solution, then sucked up my diluted iodine by unsqueezing the little dropper. I think I just didn't get the right dilution because of the stinging, and I have never gone back to trying. But I didn't necessarily have any "known" infection either, so had no real reason to try again. I originally had given it a try because I thought I had a hard to get to sinus infection because of some swelling I have in my cornea (the eye doctor said that's usually caused by an underlying sinus problem) but I wasn't sure about it and with not getting the dilution right and the sting, I decided to try other routes to nick the possible infection.