Is it possible that the hen got something in her eye or she cut or scraped her eye or near the eye? It may not be something internally that's causing this. It may be an injury. Maybe that's why the eye didn't clear completely up with the treatment you gave her. Can you give her eye another...
I would try washing her eye out with saline solution (like the kind you use on contacts). Do you know what caused her swollen and bubbly eye in the first place?