Top 8 Double Vision Causes
1. Dry Eyes
Dry eyes occur when the eyes dry out too quickly or don’t produce enough tears to keep the eyes wet. Symptoms of dry eyes include sensitivity to light, redness, and soreness. Dry eyes are a common cause of monocular double vision, or double vision in one eye.
Common causes of dry eyes include medications such as antihistamines and decongestants, medical conditions like diabetes and lupus, and the natural aging process. Dry eyes can also occur because of reduced blinking, an imbalance in tear composition, and environmental factors, including wind, smoke, and dry air.
Astigmatism is a condition in which the surface of the cornea is abnormally shaped and has two curves that contribute to blurred or double vision. Common symptoms of astigmatism include headaches, eye strain, excessive squinting, and double vision.
Many people with astigmatism are born with the condition, but others can develop it later in life. Astigmatism can also be the result of an eye injury or develop after an eye disease or surgery. People who are nearsighted or farsighted are more likely to suffer from astigmatism than those with good vision.
Cataracts are an eye condition in which the lens of the eye becomes cloudy and causes blurred, hazy, and double vision. Having cataracts is similar to looking through a fogged-up window, and it can impair the ability to see clearly in dim lighting.
Aging is the most common cause of cataracts, which tend to be more prevalent in people over the age of 40. Other risk factors for cataracts include smoking, chronic diabetes, eye trauma, and using steroid medications.
Keratoconus is a condition in which the cornea becomes thin and bulges outward like a cone to cause glares and halos at night, streaking of lights, and blurred or double vision. This eye condition can develop suddenly and quickly or gradually over several years. Many times, keratoconus develops in one eye first before affecting the other eye.
The exact cause of keratoconus is unknown, but risk factors for this condition include rubbing the eyes vigorously and having a family history of keratoconus. Certain health conditions, including asthma, hay fever, and Down syndrome, are also risk factors for keratoconus.
Pterygium, also known as surfer’s eye, is a growth that covers the white of your eye over the corner. This growth is pink, fleshy tissue shaped like a wedge. It can spread and grow toward the pupil to cause vision problems, including double vision. Pterygium might produce no symptoms or cause the affected eye to itch, burn, and feel gritty.
The exact cause of pterygium is unknown, but risk factors include excessive exposure to UV light; regular exposure to wind, smoke, sand, and pollen; and living in a sunny, warm climate.
Diabetes is a group of diseases characterized by high blood sugar levels. Type 2 diabetes is the most common type of diabetes, and it is caused by insulin resistance. Type 1 diabetes is a condition in which the pancreas produces little or no insulin, sometimes leading to dangerously high spikes in blood sugar, or hyperglycemia.
Hyperglycemia can cause fluid to leak into the lens of the eye, resulting in double vision in both eyes, or binocular double vision.
7. Graves’ Disease
Graves’ disease is an autoimmune condition that results in an overactive thyroid gland. With Graves’ disease, the body produces excess amounts of thyroid hormones to cause swelling of the neck and eyes, bulging eyes, and vertical double vision in both eyes. Eye and vision problems associated with Graves’ disease fall under a condition called Graves' ophthalmopathy.
Graves’ ophthalmopathy is caused by the buildup of carbohydrates in the soft tissue behind the eyes, which might occur because of thyroid dysfunction. While the exact cause of Graves’ disease is unknown, risk factors include having a family history of Graves’ disease, being under the age of 40, smoking, and pregnancy.
8. Brain Conditions
Health conditions that affect nerves in the brain can sometimes cause double vision, as the brain uses nerves to process visual information from the eyes. Migraine headaches, brain tumor, brain aneurysm, and stroke are some brain conditions that can cause double vision. Double vision can also be the result of pressure in the brain caused by bleeding, trauma, or infection. Treatment for brain conditions can help reverse or improve double vision.
Possible Health Conditions Related to Double Vision
- Herpes: This contagious virus causes open sores on the mouth, genitalia, and other parts of the body (including the eyes), sometimes causing double vision.
- Myasthenia gravis: In this autoimmune condition, muscles become weak and fatigued, causing drooping eyelids and double vision.
- Diabetes: Regular high spikes in blood sugar can damage soft tissue in the eyes and cause double vision.
- Graves’ disease: This autoimmune condition involving an overactive thyroid can affect vision and cause vertical double vision.
- Multiple sclerosis: This progressive nervous system disease damages the nerves in the body, including nerves in the eye, sometimes causing double vision.
- Guillain-Barre syndrome: When this progressive neurological disorder attacks and weakens nerves in the eye, it causes double vision.
Questions Your Doctor May Ask About Double Vision
- When did you start experiencing double vision?
- Have you recently fallen, suffered a blow to the head, or been unconscious?
- Is your double vision worse when you’re tired?
- Are there other symptoms that accompany your double vision?
- Do you tend to tilt your head to one side?
- Do you have double vision in one or both eyes?
- Are the double images vertical or horizontal?
- Are there any factors that worsen or relieve your double vision?
- Do you suffer from any other medical conditions?
Double Vision May Also be Known as
- Monocular diplopia
- Binocular diplopia
- Blurred vision
- Monocular double vision
- Binocular double vision
- National Library of Medicine. Dry eye syndrome. https://medlineplus.gov/ency/article/000426.htm
- National Library of Medicine. Management of diplopia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5710033/
- National Eye Institute. Facts About Dry Eye. https://nei.nih.gov/health/dryeye/dryeye
- National Eye Institute. Facts About Astigmatism. https://nei.nih.gov/health/errors/astigmatism
- National Eye Institute. Common Vision Problems. https://nei.nih.gov/healthyeyes/problems
- National Eye Institute. Cataracts. https://nei.nih.gov/eyedata/cataract
- National Library of Medicine. Keratoconus. https://ghr.nlm.nih.gov/condition/keratoconus
- National Library of Medicine. Keratoconus: epidemiology, risk factors and diagnosis. https://www.ncbi.nlm.nih.gov/pubmed/16804819
- National Center for Advancing Translational Sciences. Pterygium of the conjunctiva and cornea. https://rarediseases.info.nih.gov/diseases/4569/pterygium-of-the-conjunctiva-and-cornea
- National Institute of Diabetes and Digestive and Kidney Diseases. Type 2 Diabetes. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/type-2-diabetes
- National Library of Medicine. Ocular complications of diabetes mellitus. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4317321/
- National Library of Medicine. Double vision is a major manifestation in moderate to severe Graves' orbitopathy, but it correlates negatively with inflammatory signs and proptosis. https://www.ncbi.nlm.nih.gov/pubmed/25695893
- Harvard Health Publishing. Graves' Eye Disease (Graves' Ophthalmopathy). https://www.health.harvard.edu/diseases-and-conditions/graves-eye-disease-graves-ophthalmopathy
- National Library of Medicine. Understanding vision and the brain. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5365039/
- National Library of Medicine. Ocular herpes simplex. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2907955/
- National Institute of Neurological Disorders and Stroke. Myasthenia Gravis Fact Sheet. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Myasthenia-Gravis-Fact-Sheet
- National Library of Medicine. Multiple Sclerosis. https://medlineplus.gov/multiplesclerosis.html
- National Institute of Neurological Disorders and Stroke. Guillain-Barré Syndrome Fact Sheet. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Guillain-Barr%C3%A9-Syndrome-Fact-Sheet