Double Vision (Diplopia): Definition, Types, Causes, Symptoms, Diagnosis, and Treatment

How does Double Vision (Diplopia) Affect the Body?

Double vision (diplopia), affects a person’s body principally through their vision, causing symptoms such as headaches, nausea, distorted vision and dizziness. This can have effects on the body making it difficult to perform certain tasks as you may not feel well or be unsteady on your feet. Double vision can also affect a person’s ability to drive as, according to the Cleveland Clinic, it can affect a person's depth perception, making driving difficult and potentially dangerous.

How Common is Double Vision (Diplopia)?

Experiencing some type of double vision is very common and it can affect a person of any age, although it is more common in those over the age of 60. According to the Cleveland Clinic, approximately 800,000 people visit their healthcare providers annually as a result of diplopia. Common causes of double vision in elderly people include cataracts, an age-related eye condition caused by the natural ageing process that affects the lens. Another common cause is pterygium which is a benign eye growth of fleshy tissues that covers the conjunctiva.

1. Binocular Diplopia

Binocular diplopia is a type of double vision that only occurs when both eyes are open, according to Medical News Today. This means that when a person with binocular diplopia closes one eye, they will not experience double vision. According to Cleveland Clinic, binocular diplopia can be caused by strokes, misaligned eyes, cranial nerve issues and brain aneurysms. Within binocular double vision, there are three different categorisations which are horizontal, vertical and diagonal. Horizontal occurs when two images are side by side or overlap, vertical occurs when two images are perceived as one higher or lower than the other and diagonal is a combination of horizontal and vertical diplopia.

Below is an image of the three different types of binocular diplopia, horizontal binocular diplopia, vertical binocular diplopia and diagonal binocular diplopia.

2. Monocular Diplopia

Monocular diplopia occurs when a person experiences double vision even when one eye is shut. Monocular diplopia is the more common type of double vision and, according to Cleveland Clinic, it can be caused by astigmatism, dry eyes, cataracts and iris abnormalities. According to Medical News Today, monocular diplopia is most likely due to a problem in the eye rather than a person’s nerves. Treatment varies for monocular double vision as it depends on what causes this eye condition. Treatments may include prescription glasses for astigmatism, eye drops for dry eyes and surgery for people whose double vision is caused by cataracts.

Below is an image demonstrating what a person with monocular diplopia experiences when looking at an object.

1. Eye conditions

There are many eye conditions with symptoms that include double vision as they affect the parts of the eye that may cause vision issues. These eye conditions include cataracts, astigmatism, dry eyes and strabismus. Double vision caused by cataracts is due to cataract formation on the lens as the cloudiness of the lens causes light to scatter and form multiple, but incomplete images. According to Medical News Today, astigmatism causes double vision due to the irregularly shaped eyeball which also causes blurry vision. Dry eyes can also result in double vision as the eyes become sore and inflamed due to a lack of tear production. Finally, strabismus is a very common cause of binocular double vision as the eyes are not correctly aligned, resulting in the eyes seeing two distinct or overlapping images.

2. Nerve-Related Problems

The nerves that control eye muscle movements may be affected by certain conditions and cause a person to experience double vision. Conditions that may cause double vision due to nerve problems include diabetes, a head injury and multiple sclerosis (MS). Diabetes can lead to double vision as it causes issues with the nerves responsible for controlling eye muscle movements. A head injury such as a black eye can affect the nerves and muscles around the eye, causing a person to experience double vision. According to Medical News Today, MS affects a person’s central nervous system which includes the nerves in the eyes, potentially resulting in double vision.

3. Brain-Related Conditions

Certain brain-related conditions can cause a person to experience double vision. These conditions include a stroke and aneurysms. A stroke occurs when there is a problem with blood flow to the brain and is a life-threatening disease. A stroke may cause less serious symptoms such as double vision and nausea and other more serious ones like paralysis and aphasia. An aneurysm may cause double vision if the blood vessel that is affected presses on the eye muscle nerves according to Medical News Today.

What Triggers Diplopia that Comes and Goes?

Diplopia that comes and goes may be triggered by certain ongoing problems that affect a person’s body such as high blood pressure, diabetes, migraines and specific eye conditions such as strabismus and astigmatism. Temporary double vision is diplopia that occurs for only a short period of time and can be experienced due to fatigue, stress and low blood sugar. If you experience double vision that comes and goes or is temporary, it is important to have your eyes assessed by an optometrist as it may be an indication of a more serious problem.

1. Headache

A person with double vision may also experience headaches which are described as pain in the head or face that can feel like a constant or sharp throbbing and pressure. Double vision may occur as a headache can be centred around or behind the eye which can affect a person's vision, commonly causing blurred vision and sometimes double vision.

2. Pain Around and When You Move Your Eyes

A person experiencing double vision, also known as diplopia, may feel pain around the eye and when they move their eyes. If you are experiencing pain in and around the eyes, it is important to book an eye test so that an optometrist can assess your vision and eye health.

3. Nausea

Nausea may be experienced by people who have diplopia due to disruptions to their vision. Seeing two different objects when only looking at one can cause a feeling of dizziness that may also result in nausea. According to Buoy Health, people who have long-term or chronic double vision are unlikely to experience nausea.

4. Hazy or Distorted Vision in One or Both Eyes

Hazy or distorted vision in one or both eyes commonly occurs in people who have monocular double vision. Monocular double vision causes images to overlap and blur, which is often called ghosting. This type of vision can be experienced by people who have cataracts. Another way double vision affects a person’s eyesight is through depth perception. Depth perception is a person’s ability to judge how far an object is in relation to another object and also from the viewer. Depth perception is a very important aspect of a person’s vision and it is crucial in walking and driving.

5. Dizziness

Dizziness is commonly experienced by those who have double vision. This can be due to the distortion of a person's vision as seeing two distinct or overlapping images of one object can cause a person to feel dizzy. Dizziness caused by diplopia will commonly cause a feeling of being unbalanced rather than a spinning feeling.

When Should I Worry About Double Vision?

Double vision is often temporary and produces minor symptoms, however, if this eye condition becomes more severe and persistent, it is important to have your eyes assessed by an eye care professional. Some of the symptoms you should worry enough about to book an eye test or doctor's appointment include nausea, pain around your eyes, unsteady gait and dizziness.

What Type of Eye Doctor Diagnose Double Vision (Diplopia)?

An eye doctor, known in Australia as an ophthalmologist, may diagnose double vision or diplopia, as may an optometrist or other health care professional. A patient with double vision may be referred to an ophthalmologist if this vision issue is caused by a more serious eye problem.

What are the Tests Needed to Diagnose Double Vision?

To diagnose double vision, a person will require a standard eye test from an optometrist. In an eye test, an optometrist will ask questions about your eye history and symptoms such as when the double vision started and how long it lasts for. They will then assess your vision and eye health through various tests including a visual acuity test and a slit lamp exam. Diagnosis of diplopia will also include identifying the cause of this vision issue which may be done by an optometrist or another healthcare professional.

How Long Does Diplopia Usually Last?

How long diplopia usually lasts depends on the cause of the vision issue. Diplopia, or double vision, may be a temporary condition that goes away on its own caused by fatigue and stress or can come and go caused by ongoing conditions such as high blood pressure and migraines. If you are experiencing persistent double vision or double vision that comes and goes, it is important to see a healthcare professional.

What Type of Glasses can Help Treat Double Vision (Diplopia)?

The type of glasses that can help treat double vision (diplopia) is prism glasses. Prism glasses treat double vision as they change the direction in which light hits the retina so that the person perceives objects as a single image. Prism lenses ensure both eyes have matching light refraction, stopping the brain from perceiving images as double. Prism glasses are a type of prescription glasses that can also include other prescriptions to correct refractive errors such as nearsightedness, farsightedness and astigmatism. At Oscar Wylee, your prism correction will be found on your prescription and can be denoted using directions such as base up, down, in, and out.

Can Eye Surgery Repair Diplopia Back to Perfect Vision?

No, while surgery can be used to repair or treat diplopia that is caused by eye misalignment, or strabismus, this does not have any relation to perfect vision. Perfect vision is not a scientific term but refers to a person’s visual acuity, which measures the sharpness and clarity of their eyesight. Double vision affects a person’s vision causing them to see two wholly distinct or overlapping images. A person can experience diplopia alongside other refractive errors and can even be caused by astigmatism, but it can also be experienced on its own.

Can Double Vision (Diplopia) be Cured Naturally?

While you cannot cure double vision naturally, according to Brigham and Women’s Hospital, double vision may go away on its own, but in other cases, it may persist and require assessment and treatment. Treatment for double vision depends on the cause of this eye issue and may include prism glasses and surgery.

What are the Serious Issues Double Vision Can Be a Sign Of?

Double vision may be an indication of certain serious issues or conditions that require medical attention and assessment. One of these conditions includes myasthenia gravis which is a chronic autoimmune disease that results in weakened skeletal muscles. According to the National Institute of Neurological Disorders and Stroke, myasthenia gravis can affect the muscles that control eye and eyelid movement, meaning early signs of this disease include double vision. Double vision may also be one of the signs of a stroke which is why it is crucial you seek medical attention if you experience sudden double vision.