The white substance might be a fungus starting to develop around the eye. The white substance might turn into pop-eye which is a more serious problem that can result in blindness or even death. Add aquarium salt and perform a 50% water-change everyday until the condition is completely cleared up.
That sounds to me like maybe a fungus of some kind. You might want to go describe the problem to a fish worker in a pet shop. Many of them will be familiar with fish problems, and will be able to recommend steps to take to fix whatever it is.
For your sake, I hope it's not Ick. Ick is a common fish disease, but it can be fatal to your entire tank. Get some drops from the pet store, talk to someone who knows what Ick is.
