Double Trouble: The Low Down on Double Vision

Known medically as diplopia, the definition of double vision is the simultaneous perception of two images of a single object. The two images you see may overlap or sit side by side, and the condition can be present in one or both eyes. Double vision should not be confused with blurred vision, which is the perception of a single unclear or distorted image. Double vision is caused by a number of different conditions, some of which can be serious. Here are the causes, symptoms and treatment for double vision.


If you are experiencing temporary double vision the cause may be unconnected to your eye health. Excessive tiredness can cause your eyes to lose focus or become dry or irritated. Sleep will cure this vision impairment. Drinking too much alcohol will affect your vision, as will the effects of certain illegal narcotics. Once the effects of the alcohol or drugs wear off, the double vision will disappear. A bump on the head and certainly a concussion will cause vision impairment or loss. In this case you must see a medical doctor right away for treatment. Persistent or permanent double vision requires the immediate attention of an optometrist.


Binocular double vision means suffering double vision in both eyes. This condition is caused by the eyes essentially pointing in different directions, which sends images to the brain that are harder to collate into a single clearly definable image. So instead, the brain create two images of the same object. Binocular double vision is most often caused by a squint due to a weakened or paralyzed eye muscle. A squint will be prevalent from a young age. But other conditions are more serious and require a mandatory trip to the optometrist. Diabetes can damage the blood vessels that supply blood to the brain and the nerves that control the eye. Brain tumours and eye cancer can cause double vision by damaging the nerves in the muscles of the eye. Head injuries, thyroid problems, aneurysms, and strokes damage blood vessels or obstruct blood flow and are also possible causes of persistent or permanent double vision.


You can determine yourself whether you have double vision in just one eye by covering the affected eye, which will return your vision to normal. Monocular (one eye) double vision is less common than binocular double vision and is caused by abnormalities to parts of the eye. Some common causes are dry eye, cataracts, swelling of the eye lids, or an irregularly-shaped cornea (the transparent layer forming the front of the eye) called astigmatism. Macular degeneration, which is the deterioration of the central portion of the light-sensing retina at the back of the eye, may be more prominent in one eye in the earlier stages of the condition.

Double vision should never be ignored. Whether you’re experiencing this condition often or incidentally, it is crucial you visit your local eye-care expert for a proper diagnosis as soon as possible. At iSight Optometry we use advanced techniques to provide comprehensive testing, diagnosis, and treatment options for all eye-related issues. Contact us today or read more about our team to learn why iSight Optometry has earned its reputation as Kelowna’s pre-eminent optometry clinic by exceeding our patients’ expectations for over 60 years.