Though it stresses the fish out a bit, infections on the eye are hard to get rid of and often end in the death of the fish, I would suggest using Betadyne, its the same stuff that doctors use to sterilize prior to sugeries. Basically what you should do is dip a q-tip in the stuff, then very very gently dab the area infected. Just for a precautionary thing I'd also treat your tank with Melafix, the melaluca oil in the solution helps both fight off further infection and stimulates healing.