Double vision, also known as diplopia, is when you see two of a singular object. It can be temporary or permanent and can also occur suddenly due to several causes, which you will learn about shortly.

The two images aren’t usually the same, with the additional or fake image usually appearing with minor detail and depth, hence the term ‘ghost image.’

While there are various reasons and causes for diplopia, several solutions exist. These include prism glasses for double vision, surgery, therapy, and a few others, more of which later on. 

There are three broad categories of double vision. 

Horizontal diplopia

Horizontal diplopia is a double vision where the two objects are separated horizontally.

Vertical diplopia

Vertical diplopia is the most common form of double vision, where two images are separated vertically.

Monocular diplopia

When double vision remains after one eye is closed, it is known as monocular diplopia.

Sudden onset of double vision and any double vision that persists can be a sign of something severe, and you should consult a health care professional immediately. 

Symptoms Associated With Double Vision

While double vision is a condition in and of itself, it can also be a symptom of other conditions. It can also either occur independently or as one of many symptoms. Some of the most common symptoms associated with double vision include: 

  • Headaches & Migraines
  • Nausea & Vomiting
  • Dizziness And Fainting
  • Droopy Eyes
  • Poor balance
  • Misalignment of the eyes
  • Eye pain 
  • Weakness in eyes

The occurrence of double vision with one or more of these other symptoms can mean various things. It is often a case of ‘chicken or egg’ in terms of which symptom caused the other. 

It is particularly true when it comes to migraines and double vision. Medical professionals can decipher the root causes and treat you accordingly, and you should consult them when you experience sudden or persistent double vision. 

Causes Of Double Vision

Diplopia can be temporary or permanent. Short-term diplopia can happen for a few reasons: alcohol or drug consumption and abuse, extreme fatigue, rapid motion like roller coasters, and physical trauma. 

Short-term double vision is usually harmless and corrects itself after the temporary cause is over. It isn’t always the case, though, and you should still seek medical assistance in some cases. 

Long term or recurrent double vision is usually a sign of something much more severe, and the causes can include:

Strokes

The loss of eye muscle function, often in one eye after a stroke, is prevalent and can cause diplopia.

Head injuries

While physical trauma can result in short-term diplopia, severe head injuries can cause long-term double vision, a sign of significant damage. 

Brain aneurysms

Traumatic brain injury that leads to an aneurysm and bleeding on the brain can often cause long-term double vision.

Disorders of the eye

Various eye conditions can cause double vision, including keratoconus, cataracts, and even something as mild as dry eyes.

Refractive surgeries

Surgeries to eliminate the need for contact lenses and glasses such as LASIK or PRK surgery can cause either long or short-term double vision. While this usually clears up quickly, it can last for months and, in some cases, requires another surgical procedure to correct it. 

Strabismus

Crudely known as being ‘cross-eyed,’ strabismus is a congenital condition that causes the two eyes to be misaligned. As a result, strabismus sufferers experience diplopia because each of their eyes is focused on images differently due to misalignment and the brain’s inability to correct the double vision. 

Strabismus can cause the eyes to either be crossed inwards, outwards or one up and one down. Occasionally, the brain does adapt to this and attempts to ignore the information coming from one of the eyes. It can result in other problems such as amblyopia, also known as ‘lazy eye.’ 

Treatment Of Double Vision

As mentioned, double vision can be successfully treated in several ways, depending on the causes, severity of the symptoms, and frequency. 

Prism glasses are highly effective in treating double vision, particularly long-term double vision caused by eye movement problems like strabismus. 

Lenses are either permanently or temporarily modified with prisms that refract light before entering the eyes. In doing this, light is evenly focused on both retinas in the same place, correcting the root cause of this type of double vision. 

Other treatments include surgical procedures and various vision therapies, some of which try to strengthen weak eye muscles that are causing double vision. Keeping one eye closed with an eye patch is also used in some cases. Treatment involving special contact lenses can also be used, and other prescriptions besides prism lenses can be effective.  

When double vision is a symptom of another disorder, it will usually go away when cured. However, the treatments above can be attempted when it doesn’t go away. 

The treatment, however, really does depend on several critical factors, and that’s why it’s imperative to seek professional advice if you experience sudden or prolonged double vision.