Green drainage is usually a sign of infection. Allergies usually cause clear drainage. You need to take her to doctor.
Have you seen the green stuff or just been told about it? When they took her to the doctor, what did the doctor say or do? She may have some eye drops they gave her. I'd say it is allergies or an eye infection (that is rarely serious). But they have sought medical attention for her---- so am guessing they are on top of it. goodl uck