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.
Blurry vision may be experienced in one eye or in both eyes, depending upon the cause. Blurred vision can also be a symptom of numerous conditions that do not directly involve the eye, such as migraine or stroke. A number of medications may also lead to temporary blurring of vision as a side effect. Sometimes, blurred vision is associated with other symptoms, depending upon its cause, including headache, sensitivity to light, or redness and irritation of the eyes. Medically Reviewed by a Doctor on 8/24/2015.