I've had a few fish with pop eye. Treatment is actually pretty simple. You can use the bottled medication "Melafix" which I personally love, but have never used it for pop eye though it is used for treating it.
I use a home made remedy and add some Epsom salts into the tank. I forgot the dosage you may need to google it but I treated a molly with Epsom salts and within 4-5 days it cleared it up and she was back to her normal self