Popeye has any number of origins, but most all are bacterial in nature. As was stated previously it is generally caused by fluid buildup behind the eye, but can also be caused by hemoragic swelling, and combat wounds.

I would treat with an anti bacterial such as Furazolidone, or Furaloid, and medicated food such as Krill soaked in Kanamyacin (any antibiotic will have to be mixed down with R/O) or perhaps the Jungle medicated foods. Full treatment is 10 days to two weeks

If the overall color around the eye is light colored give it a shot, but if the color is dark or bloody please euthanize the animal. That is a hemoragic swelling and is often incurable by the time you are witnessing sypmtoms, and is a miserably painful way to die. Best of Luck, Prof M