| What are your water parameters right now?
Does the eye look like it is covered by a film or otherwise cloudy?
Did you perform water changes between doses of maracyn?
When is the last time you added new fish?
How long have you had this fish in your tank?
A picture would really help out here quite a bit. It is very hard for anyone who is not a vet or well educated in fish and diseases to diagnose problems like this accurately in person, not to mention just by description. There are other causes for Popeye that are not bacterial in nature and more parasitic in nature (eye flukes) and so if this truly is the case with your fish, maracyn may have little or no effect on it at all. | 
