Thank you for getting back to me. Bacterial infections are the most common cause of a cloudy eye, and such infections can spread to the entire body. I do want to mention some other possibilities. An injury could be responsible. In that case, the condition is probably permanent. Another possibility is a tumor behind the eye.putting pressure on it. Again, there would be no treatment.
The problem is that the Furan you used treats both gram negative and gram positive bacterial infections. Erythromycin treats only gram positive infections. But, between the two of them any bacterial infection Owen might have should have been cured. If you want to try yet another antibiotic, Kanamycin has been found to be especially good against eye infections. Because Owen is floating on his side, I suspect the infection is not only in his eye. If he has a tumor pressing on that eye, it is likely that he has tumors affecting other organs, too.
I'm sorry to give you less than good news, but I believe you deserve honesty. You are not likely to get good results with any over-the-counter medications. Your best chance of saving Owen is to have him examined by an aquatic vet. Many of them do make house calls, so you wouldn't have to transport Owen anywhere. This link will take you to a directory of fish vets:
The other option would be to continue to try other medications, such as kanamycin. If he doesn't improve, the most humane thing to do might be to end his suffering. If you decide on that choice, let me know, and I'll tell you the most humane method (there's no additional fee).
I hope that whatever you decide to do, it will work out well. If you have more questions, just let me know.