Is the popeye in one or both eyes?
If it's one eye, it's most likely caused by an injury and it can be cleared up with just Epsom's salt.
If it's both eyes it's most likely bacterial and any medication with a Kanamycin base can cure it.
But even if it is bacterial, you should still do the Epsom's salt. It will help relieve the fluid pressure and help prevent the eye from actually popping.
I've had 2 cases of popeye. One with a Gourami and one Electric Blue Cichlid. Both are still doing great. And all I used was the Epsom's salt, on both.
First no matter what kind of popeye it is, you need to isolate the sick fish. It may only be from an injury but even if there is a 5% chance that it's bacterial, you don't want to spread it to all you other fish.
The Articles that I've read on using Epsom's salt for injury induced popeye, recommended 1 tablespoon Epsom's salt for every 5g of water.
Starting with a 50% PWC the add the Epsom's salt. I used 2 Tablespoons of the Epsom's salt for every 5g of water, and the popeye was gone in 3 days. The longer the eye is swollen the more damage is done. Using 2TBS instead of 1TBS didn't cause any negative affects to my cichlid in anyway. It in fact saved his eye.
Then repeat the PWC every day and replace the Epsom's salt for 3 days or until the popeye is gone. You don't need to worry about the Epsom's salt burning your fish like salt does, it's not sodium, it's magnesium.
Good luck