Well it's a good sign that he's still swimming and eating but the other symptoms are cause for concern.
More information is needed:
How long has this fish been showing these symptoms?
How many and what species of fish are in the tank? What size tank? How long has it been set up?
Do you know your water parameters?
Cloudy eye often indicates a problem with water quality so you could start off with testing your water for ammonia, nitrite and nitrate if you haven't already done so and then do a 40% partial water change with a good quality declorinator.