He Lives In A Caravan.....

I think I may have a case of popeye on a Penguin.
Any help would be appreciated.
I only noticed it because the light from my dinning room light has caught her eye and was very sparkly compared to the rest of the shoal who were all facing the same direction at roughly the same depth.
I sit at the same spot at my table every evening and didn't see it last night so it is a very recent issue. Her eye isn't obviously over sized, but is noticeable compared to the shoal.
 None of the rest of the shoal seem to be affected. She has been in the wars with a very tattered tail, growing back nicely though, so maybe just feeling run down has contributed to it.
I will try and get a couple of pictures of her.
What would be the best course of action to take?

It just seems to be her right eye and it isn't cloudy as I've seen described.
I'll do frequent water changes to keep the risk of infections down to a minimum.
I doubt it was Nick, but could be wrong, the fry that he brought with him he has left alone to do their own thing and doesn't seem to be guarding any areas. He's even tried to mingle with the shoal to no avail lol.

I've attached a photo, which is blurred but does show the shinning I mentioned.