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.
You might also have blurry vision if youâre developing cataracts. Cataracts cause the lens of your eyes to become cloudy. People with diabetes tend to develop cataracts at a younger age than other adults. Other symptoms of cataracts include: faded colors; clouded or blurry vision; double vision, usually in just one eye; sensitivity to light