There are common indicators to determine if an eye infection is caused by a viral or bacterial infection. A bacterial infection is usually identified by a green or yellowish discharge, while a viral infection will have a clear or white discharge. Itchy eyes are more commonly associated with allergic conjunctivitis, which is highly contagious and quite unpleasant. If you prescribed antibiotics for conjunctivitis and it does not resolve within 3 to 4 days your doctor may suspect the infection is viral. Viral conjunctivitis (pink eye) is the most common of eye infections and can often be accompanied by upper respiratory symptoms.