Seeing Double? How to Treat and Prevent Double Vision

Many of us are suckers for a good two-for-one deal; but when it comes to vision, seeing double can be frustrating and even alarming. Diplopia, or double vision, happens when someone sees two images of a single object. This vision problem can occur all the time or may happen off and on, depending on the severity and underlying issue.

There are three different types of diplopia:

• Binocular double vision: Both eyes do not work together as they should, and double vision disappears if you cover one eye.
• Monocular double vision: Double vision is present in only one eye, which leads to a ghosting effect where the two images are only slightly separated.
• Physiological double vision: Occurs when only background images, or images not being focused on, appear to be doubled. This type of diplopia is usually the issue when a child mentions seeing double.

What causes double vision (diplopia)?

Unless you have a vision issue, you most likely take for granted the complex process of opening your eyes and seeing a single, clear image. Eyesight involves an orchestration of the vision system from the cornea to the eye muscles to the nerves that carry visual information to your brain. A problem with any part of this visual system can lead to double vision.

• Cornea: Problems with the cornea, which does most of the focusing on incoming light, can lead to double vision in one eye only. Corneal damage can happen in several ways:
  • Infections can distort the cornea.
  • Scars can alter the cornea.
  • Dryness of the cornea can create double vision.
  • Refractive surgery, such as LASIK or PRK, can lead to double vision. The problem usually clears up within weeks or months. Eye drops can help, but in some cases a second procedure may be necessary. 
• Eye lens: The eye’s lens is behind the pupil and helps focus light on the retina. A common lens problem that can lead to diplopia is a cataract.
• Eye muscles and nerves: If a muscle in one eye is weaker than the other, then the two eyes will not move smoothly together and this can cause double vision. Similarly, some conditions can damage the nerves that control the eye muscles and can lead to double vision. Muscle and nerve problems can result from:
  
  • Graves' disease, a thyroid condition that affects the muscles of the eyes, causes vertical diplopia where one image is on top of the other.
  • Myasthenia gravis, an autoimmune illness that blocks the stimulation of the muscles by the nerves inside the head. Signs of this illness include double vision and drooping eyelids.
  • Cranial nerve palsies, the paralysis or loss of coordination of one or more muscles that control the position and coordination of the eyes
  • Multiple sclerosis, which affects the nerves in the brain or spinal cord
  • Guillain-Barre syndrome, a nerve condition that causes progressive weakness
  • Diabetes, which can impact the nerves that help muscles move the eyes
• Brain: Many different causes of double vision originate in the brain and affect the nerves that control the eyes:
  • Strokes
  • Aneurysms
  • Increased pressure inside the brain from trauma, bleeding, or infection
  • Brain tumors
  • Migraine headaches

Symptoms of diplopia

Double vision can occur with no other symptoms, and you’ll know if you are experiencing it. But depending on the underlying cause of diplopia, other symptoms may be present, such as: 

• Misalignment of one or both eyes, such as a wandering eye or a cross-eyed appearance
• Pain when moving one or both eyes
• Discomfort or pain around the eyes, such as in the temples or eyebrows
• Headache
• Nausea
• Weakness in the eyes 
• Droopy eyelids

How is double vision (diplopia) treated?

You can work with your eyecare professional to identify and treat the underlying cause of your diplopia. Surgery may be the answer if weak eye muscles are the cause, while other issues, such as diabetes and myasthenia, can be treated with medications. If diplopia can’t be reversed, there are treatments to help people manage and live with double vision. Wearing an eye patch or prism glasses, which help align the two images into one, can help.

Can you prevent double vision (diplopia)?

Preventing diplopia starts with preventing the underlying cause. Here are a few tips to keep your eyes healthy:

• Control your diabetes: Patients with diabetes who follow treatment plans have a lower risk of developing double vision. Also, because type 2 diabetes can develop as a result of lifestyle, people who eat a healthy and balanced diet, get plenty of exercise, and maintain a healthy weight are much less likely to develop diabetes and subsequently double vision.
• Prevent the development of cataracts: Keep your eyes healthy and avoid cataracts by wearing sunglasses, refraining from smoking, and eating a healthy diet.
• Soothe dry eyes: Keeping your eyes well-lubricated can help prevent double vision. Also, try to minimize eye strain from prolonged computer use, which can lead to dry eyes.
• Protect yourself from head injuries: Prevent head injuries by wearing a seatbelt in the car, a good helmet when riding a bike or motorcycle, and appropriate headgear and glasses when using large machinery and playing sports.