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 itâs moving too little, it can become irritated and red with blurry vision. Keep in mind most people should be able to wear contact lenses for up to 12 hours comfortably if it fits right. Allergies: Allergies are a major reason why people experience discomfort while wearing contacts. Many either change their wearing habits or abandon them all together until the allergy season has passed.