What is double vision (diplopia)?
Double vision can occur with one or both eyes. If it’s in one eye when the other is closed, it’s less of a concern, but it’s still serious. If it occurs when both eyes are open, it could indicate a greater disorder.
When you open your eyes and see a clear, lonely image, you may take it for granted. But it is the result of a complex process that requires many parts of your vision to work together seamlessly.
To understand what can go wrong, it helps to know the parts of the eye and how they work together.
Causes of double vision
Temporary episodes of double vision can occur for many reasons, such as drinking too much alcohol or being too tired. This type of short-range double vision is usually not a cause for anxiety.
But if diplopia is long-lasting or keeps coming back, the reasons may include:
- Head injury
- Brain tumor
- Brain swelling
- Brain aneurysm
Ahead or brain injury, tumor, stroke, or related condition can cause double vision to appear suddenly. After examining you, your ophthalmologist may refer you to a specialist, such as a neurologist or neurosurgeon, for further testing and treatment.
- Corneal irregularities
- Dry eyes
- Refractive surgery
- Cranial nerve palsy
- Double vision and strabismus
Symptoms of double vision
Double vision can occur without other symptoms. Depending on the cause, you may also notice:
- Misalignment of one or both eyes
- Pain when moving the eye
- Pain around the eyes, such as eyebrows
- Weakness in your eyes or elsewhere
- Droopy eyelids
Diagnoses of double vision
Diagnosing double vision as monocular or binocular is generally straightforward. Determining the cause can be more difficult. If you have diplopia, your symptoms and visual experiences will help in the diagnosis.
When you visit your doctor, they will take note of your symptoms and run some tests to look for additional vision problems. They will also likely perform a brief test to diagnose the type of diplopia.
Once you have a diagnosis of diplopia, the work of finding a cause begins. To do this, your doctor will likely perform three types of tests:
Take stock of your current health status
You and your doctor may spend some time updating your medical history. This includes:
A complete history of your symptoms: Fully describing your vision problems to your doctor can help you eliminate possible causes and decide which tests may be helpful. Make sure to report any unusual symptoms you’ve experienced to your doctor, even if you’re not sure they’re related to your vision problem.
Your personal medical history: Your doctor may consider underlying factors such as diabetes, thyroid problems, or neurological disorders that could be causing your vision problems.
Your family health history: If your family members had eyesight problems or illnesses that can cause double vision, tell your doctor. These problems can be a good starting point for your own diagnosis.
A complete physical exam can help your doctor find and identify possible causes of your vision.
- Blood tests to look for an infection
- Eye exam and dilated eye exam
- Eye movement tests
- Toxicity tests
- Blood sugar readings
- Imaging tests: Such as a CT scan or MRI
Treatment for double vision
Generally, treatments for double vision include surgery, vision therapy, prismatic lenses in glasses, or medications.
It is important to have a complete eye exam to help determine the cause of double vision as soon as possible. Your ophthalmologist can treat diplopia or refer you to a specialist (such as a neurologist).
If you have sudden diplopia that you ignore and then disappear for a long period of time, this may mean that your brain has disconnected one of the images (suppressed it). Although this is certainly more comfortable and acceptable to you, it is not a good sign. The removal could be masking a serious problem that needs to be addressed.
In fact, the condition can be a matter of life and death, like a brain tumor or aneurysm. See your neurologist right away if you develop double vision.
Some situations that can cause diplopia are difficult, if not excruciating, to fix. Furthermore, strokes and nerve palsies cause fluctuating diplopia that cannot be measured accurately enough to correct it.
In these circumstances, you may need an adjustment period so that you can learn to live with the symptoms. Your neurologist can help by prescribing a prism, patching one eye for periods of time, or prescribing special contact lenses or other treatments.
Every feasible cause of double vision has potential complications. The causes of double vision can range from something easily correctable to something more complicated, such as a chronic illness.
Some people with diplopia may experience nausea or vertigo due to the altered field of vision. Others may experience eyestrain and sensitivity to light or sounds.
Life-threatening circumstances, such as infections or brain tumors, can cause diplopia, but these cases are rare. In these cases, severe eye pain or headache often occurs along with visual changes. Any headache followed by changes in vision is considered life-threatening and needs immediate medical attention.
Departments to consult for this condition
- Department of Neurology