Blurry vision refers to a lack of vision details and visual disturbances. Infection, inflammation, trauma, pregnancy and other ways can lead to blurred vision, cold is one of them. Blurry vision for a cold can be caused by an overdose of medicine, so you should be careful and read the medicine labels. If you have allergies, it can cause the tear ducts to produce more tears and cause the eye site to become blurry. Sometimes, temperature weakness is often associated with a weak or constricted lymph system. Good vision is very depend on a healthy lymph system, some signs of a weak lymph system are under developed parts of your body which will even lead to your headaches. If you have a cold and blurry vision for a long time, you should take a doctor's advice.