Hi,
I have not heard the term "sticky eye" before so am not sure what this is.
There are several eye complaints piggies can get,infection,poke injury, hay seed stuck in the eyelid,cataract and fatty eye.
I think what you are referring to is a foreign body in the eye.This causes sticky discharge.
The symptoms are wetness and "stickyness" around the eye.
The treatment is to flush the eye with Optrex or similar,and gently massage under the lower lid from the corner out.