Double vision, or Diplopia, is an eye problem that should never be ignored.
Specifically, double vision is the perception of two images of a single object seen adjacent to each other (horizontally, vertically, or obliquely), or overlapping each other.
Double vision is referred to as “monocular” when the doubled image is perceived by an eye that is tested by itself. In contrast, “binocular” double vision occurs when each eye sees a single image when tested alone, yet a doubled image is seen when both eyes are open.
What Causes Double Vision?
An abnormality in any part of the vision system can cause double vision. Corneal infections such as Herpes Zoster (Shingles) can damage the surface of the eye resulting in image distortion. Cataracts may also lead to double vision.
Other conditions that interfere with proper focusing of light include corneal irregularity from keratoconus, swelling or scars, and retinal conditions such as epiretinal membranes.
If a muscle in one eye is weak, it cannot work well with the other eye. Myasthenia Gravis and Graves Disease are examples of conditions that often weaken eye muscles. Sometimes nerve damage is the culprit in double vision. Multiple Sclerosis, Guillain-Barre Syndrome and diabetes all affect the nerves that control the eyes.
Origins in the Brain
Double vision can often originate in the brain due to:
Treating Double Vision
Whatever the cause, sudden, unexplained double vision requires immediate medical attention, as this can indicate a serious underlying condition.
Upon seeing an eye doctor, he or she will determine the underlying cause of your double vision. Once the cause has been determined, treatment is tailored to the underlying condition.
For example, diplopia stemming from refractive errors (myopia, hyperopia, astigmatism) can be corrected with glasses or contact lenses. Similarly, artificial tears, anti-inflammatory drops, punctal plugs, warm compresses, and a variety of other treatments can be used to treat dry eyes.
These examples are rather benign. But as noted above, double vision can indicate a far more serious condition. If you experience double vision, contact your eye doctor immediately.