I'm sorry, I forgot what the "tank thing" was.
Cloudy eye can have several reasons, from injury over poor water quality to bacterial infections (for the mentioned reasons or other).
So what are your water parameters please, if you know? It sometimes goes away again with keeping the tank and water real clean and maybe adding some aquarium salt temporarily. However if it doesn't, you might want to get a treatment against bacterial infections. In case it is white fuzzy stuff on the eye rather than "milky" that might be a fungus then, but that is often a secondary infection to a bacterial one in my experience.