Discovering Vision Therapy Blog

The Causes of Double Vision

Posted by Greg Mischio on May 11, 2011


Double vision, or diplopia, occurs when your eyes don’t work as a team.  When your visual system is working correctly, both eyes should point in the same direction at an object.  Your eyes see two different images, which your brain combines to produce a single, 3D image.

If your eyes are not pointed at the same spot, your brain won’t be able to combine them effectively.  You’ll then experience double vision.  You may feel nauseous, dizzy and have trouble keeping your balance.  

Experiencing double vision is no picnic, and in some cases, it can be quite scary.  Once you understand the root causes of double vision, however, you can work with an eye care professional to find an appropriate treatment.

Living with double vision

Double vision can range in its severity.  If you only experience a small amount of double-vision, you may only notice a slight shadowing effect.  At the other end of the spectrum, significant double vision will result in two distinct images. 

Generally, the more fatigued someone becomes, the worse the double vision will be.

Surprisingly, people who have double vision can learn to live with it.  It’s not entirely comfortable, but there are many stories of people who find ways to adapt and function in society, despite their double vision. 

What are the causes of double vision?

A number of different conditions contribute to double vision:


Strabismus occurs when one of the eyes is turned inward, outward, up or down.  Not all types of strabismus will cause double vision, but some do. 

Head trauma

People with brain injuries often see double to some degree, as head traumas can cause strabismus and double vision.


Presbyopia is a Greek work that literally means “old eyes”.  It occurs at the age when a person needs reading glasses.  Generally, as people age, any long-standing vision problems that have been compensated for will start to emerge as the visual system breaks down.  Double vision may result.

Convergence insufficiency or convergence excess

A more mild case of double vision can be related to these conditions, both of which are related to the eyes’ ability to team. The double vision typically occurs for near vision, such as when reading. Many people describe the double vision as “the words move around on the page” rather than noticing that the words are splitting apart.

What can be done to correct double vision?

Please note that anyone who is experiencing a recent onset of double vision needs to be evaluated by an eye care professional or neurologist immediately.  A sudden onset of double-vision could be a sign of pathology in the brain.

Once any pathology has been ruled out or treated, you can then begin to explore other types of treatment.  A very effective treatment for double vision is optometric vision therapy.  Through a series of activities, vision therapy can help you gradually retrain your eyes to work together.

 Vision therapy is a treatment designed to work on the underlying problem and, in best cases, eliminate it. Other forms of treatment designed to compensate for the problem include prism glasses and occlusion (covering an eye or part of the vision for an eye).

 At The Vision Therapy Center, the doctors have special training in prescribing the most effective glasses, such as prism glasses, and/or occlusion for best functioning. These treatments can be used alone or in conjunction with vision therapy for the best outcome.

Keep in mind that the amount that double vision can be reduced will depend on your visual condition.  A functional vision test is the first step in determining the extent of your double vision, and what types of treatment can be used to correct it.

(Photo by Koonisutra)

 The Vision and Learning Guide from The Vision Therapy Center. Learn how undetected vision problems can impact a child's ability to learn.  Download your free Vision and Learning Guide.

Topics: Double Vision