A person should contact a doctor about blurry vision when it is accompanied by other warning signs such as eye pain and sudden or partial loss of vision, reports the Merck Manuals. When these symptoms occur, people should get emergency medical attention as soon as possible. The National Institute of Health concurs, especially if pain and eye redness are present along with blurry vision.
There are many possible causes of blurry vision, including retina damage, glaucoma, cataracts and corneal abrasion. Certain medical conditions, such as diabetes, may also cause blurry vision. However, it may be a temporary symptom due to elevated blood sugar, states WebMD.