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.
Keep in mind that many eye conditions can cause some blurred vision, including pink eye, allergies, dry eyes and even a lot of near vision work. Most of these are not emergency situations. Quick Tip: For mild blurry vision, try resting your eyes. If the blurry vision persists, make an appointment for an eye exam.