Diplopia is when you see two images of one object. You might know it by its more common name, double vision.
Double vision can be a symptom of many different issues. It’s not usually serious, and most cases are temporary. It’s not usually a cause for concern for your wider health but in some cases double vision can be linked to more serious underlying health conditions.
If you are seeing double, visit your optometrist for a diagnosis especially if it is new, comes on suddenly or is accompanied by headaches. Treatment will depend on the underlying cause of the problem. In many cases, vision issues will go away with the right treatment.
Double vision, or diplopia, causes you to see two images of the same thing when there is only one there. You can have double vision in one eye, or in both eyes. (1)
Depending on the root cause of your double vision, you may also experience headaches, nausea and pain around your eyes. You may notice that your eye hurts when you move it around, or that your eyes don’t respond in the same way at the same time. This can make you look cross-eyed or like you have one eye that ‘wanders’. Double vision can also be accompanied by droopy eyelids or eye weakness. (2)
Many different conditions can lead to double vision. It can occur in one or both of your eyes depending on the underlying cause. (3) (4)
Double vision affecting both eyes (binocular)
Binocular double vision can be a result of problems in the muscles, nerves or brain. It usually happens because your eyes aren’t working together. Causes can include: (5)
• Strabismus: Crossed eyes due to problems with the eye muscles.
• Diabetes: a disease that causes high blood sugar that can damage the nerves potentially resulting in vision loss.
Other less common conditions that may cause double vision include nerve damage, cranial nerve issues, myasthenia gravis, graves’ disease or brain issues.
If you see one image as higher than the other, then this is called vertical diplopia. If the images repeat side by side, it is called horizontal diplopia.
Double vision affecting one eye (monocular)
Monocular double vision is often due to a physical problem in the affected eye. These can include:
• Keratoconus: when your cornea (the clear covering or your eye) gets thinner and changes shape.
• Astigmatism: where your cornea isn’t a perfect shape so it doesn’t focus properly.
• Cataracts: a common condition where a buildup of protein in your eye covers your lens (the opening of your eye that controls and focuses the light that enters your eye) blocking your vision.
• Dry Eyes: where the eyes don’t produce enough tears to lubricate the eyes.
• Pterygium: a rare, non-cancerous growth on the tissue that covers your eyelid and eyeball (conjunctiva).
• Ill-fitting glasses or contact lenses that distort your vision.
You should visit your optometrist for an eye exam even if it comes and goes, or you are only experiencing temporary double vision. It’s especially important to have it checked out if you are experiencing sudden double vision or double vision for the first time.
Diagnosing double vision is relatively straightforward. We will talk to you about your symptoms and vision and do some simple eye tests.
Diagnosing the cause of double vision can be harder to pinpoint. We will ask questions about your personal and family medical history, as well as any recent changes in your health. Whether you have vertical double vision or horizontal double vision can also be useful to help determine the cause of your symptoms. (6) If you only have double vision in one eye, you may not need any further tests. If you have binocular diplopia, we may refer you to an ophthalmologist for further tests and treatment. (7)
The treatment for your double vision will depend on the cause of your condition. The most common treatments involve correcting your vision with glasses or special lenses. You might also be given an eye patch as a temporary solution while you wait for other treatments to take effect. Eye exercises can be an effective treatment to help strengthen weak muscles. For some health conditions, medicines can help to treat or control the progress of the disease. Other conditions may need to be treated with surgery, for example pinched muscles, cataracts, or other underlying health conditions.