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.
If you develop red eyes while wearing contact lenses, consider it a warning sign. While a contact lens may seem small and harmless, you must keep in mind that it is a foreign body resting on the surface of your eye. If your eyes turn red while wearing your contacts, it may mean you are simply overwearing them. However, there are many conditions that can cause increased eye redness while wearing contacts. Below are the top seven reasons why your contacts may be causing red eyes.