I'm not so certain that the issue is the definition of the term normal, so much as it is the value (positive or negative) or association (healthy vs. unhealthy) the term implies in a medical or social context.
One of the most common reasons for blurry vision while wearing contacts is that your eyes are dry. Some people have a medical condition that causes dry eyes, called dry eye syndrome, but others' eyes are irritated by the contacts themselves.
Other Conditions causing ocular itching and burning found on other pages: 1  Conjunctivitis - pink eye, with redness, discharge, lid swelling. 2  Contact lens problems - contact lens use can cause itching and irritation, due to allergy or improperly fitting lenses. 3  Episcleritis - localized eye injection with mild symptoms.