Double vision: diplopia as a sudden, occasional but also permanent visual impairment?

Double vision is a problem that can be caused by a number of different diseases and conditions. And it may not just be a vision problem, but a multitude of other muscular, neurological and systemic diseases.

You often ask:
What causes double vision? What does it mean if it occurs all at once, suddenly?
Can it occur only occasionally or together with blurred vision?
Is it possible that it occurs with cervical spine pain?

In the less severe cases, it is caused by overexertion of the eyes in the form of dry eye or excessive fatigue.

Double vision = diplopia.

Double vision is a condition in which we perceive one object twice. It is the simultaneous seeing of two images with a sideways shift, horizontally, vertically, but also diagonally.

And for example...

A large percentage is caused by malfunctioning of the eye movement muscles. This is when squinting can be seen externally. This misalignment of both eyes causes the image being viewed to not be received in the correct direction on the retina of the eye.

When one eye is covered, the double perception disappears.

However, we know of cases where such overlapping of one eye does not help and we still see double.

Accordingly, diplopia is also divided into binocular and monocular.

Division of diplopia:

1. binocular - disappears when one eye is covered - each eye projects an image onto a different part of the retina
2. monocular - perception of two images with one eye, or perception of multiple images - the condition is referred to as polyopia

1. How is it in the binocular form?

In this case, the images of the two eyes are projected onto the retina differently. In most cases, the acuity is good and therefore they are projected equally.

A large percentage of the binocular form is due to squint. One eye focuses on an object and it is sharply imaged at the sharpest point on the retina (fovea of the macula) of that eye.

However, the other eye is misaligned and the light rays are directed away from this point of sharpest vision.

Light rays that fall directly on the point of sharpest vision are evaluated by the brain as objects directly in front of the person.

On the other hand, rays that fall outside this area are perceived in an off-axis manner. They can be offset in different directions, horizontally (left, right), vertically (up, down) or even rotated when the image is slightly rotated.

The result is that the brain receives two different patterns. When they are combined, double vision is created.

Didn't you squint, had good eyesight?
And suddenly you have double vision?

Squinting also occurs in adulthood. At this age, the brain is no longer plastic enough to cope with the perception of double images as it is in childhood.

Children, even if they are visually impaired, complain much less about double vision.
Asking why?
Read more in the section on childhood below.

Of course, there can be several causes. One example is also myopia (usually in children) or astigmatism. In both cases, the underlying cause is the blurring of the image falling on the retina, or the impact of several images on the retina (simplified).

Moreover, the binocular form is divided into intermittent and permanent.

The intermittent form is characterised by alternating periods of onset with periods of subsidence. Difficulties are exacerbated by eye strain and eye fatigue.

This type of intermittent diplopia is characterised by, for example:

• Migraine
• painful cervical spine - may be associated with headache, dizziness and double vision and other visual disturbances
• uncorrected refractive errors of the eye or incorrectly weakly or strongly corrected refractive errors
  • myopia
  • farsightedness
  • presbyopia, hyperopia, also known as old-age vision
• autoimmune diseases such as myasthenia gravis
  • affects the neuromuscular disc and the transmission of impulses
  • the ocular form, which in approximately 20% is manifested by involvement of the eye muscles

The permanent form is represented by:

• damaged oculomotor nerves, muscles with strabismus
• paralysis of the cranial nerves (nerves III, IV and VI, which control the eye muscles)
• damage to the optic nerve and visual centre
  • inflammation - of the nerve, of the brain
  • oppression of the nerve, which can cause bleeding or a tumour
  • eye and head trauma and concussion
  • intoxication, i.e. poisoning (alcohol, CO gas)
  • drugs (antiepileptics, anticonvulsants, hypotonic drugs, sedatives, ketamine, drugs acting on the nervous system)
  • excessive fatigue of the eye movement muscles
• diabetes with diabetic neuropathy, retinopathy - diabetes mellitus with complications
• multiple sclerosis and other degenerative neurological diseases
• thyroid diseases - especially Graves-Basedow disease

Alcoholism causes damage to the brain and nervous system.

High blood pressure is also a dangerous condition that can cause various cardiovascular and neurological problems. In this case, hypertension can be referred to as hypertensive crisis.

A health and life-threatening complication that can manifest itself in double vision is also a stroke.

2. Monocular form...

Affects only one eye or optic nerve and center. And similarly in a situation where the image is projected onto several sites on the retina.

Double vision is present in only one eye, such as the left eye.

When diplopia is present in one eye, we initially consider damage to the eye and malfunction of the components of the eye.

Examples include keratoconus, a disease of the lens, but also damage to the optic nerve or the visual centre that is in the eye.

The table gives examples according to the form of double vision

Summary of causes:

• Inflammatory diseases, abscess, examples include herpes simplex or herpes zoster
• eye disease - inflammatory, traumatic, other
• refractive errors of the eye
• strabismus
• aniseikonia - perception of different size of images
• treatment with drugs that affect the nervous system, brain
• nerve degenerative diseases
• pain in the cervical spine
• tumour diseases and cancer
• botulism
• alcohol, drugs, as well as marijuana
• diabetes
• Lyme disease
• migraine and similar headaches
• cardiovascular disease, hypertension, stroke
• sinusitis - inflammation of the sinuses
• increased intracranial pressure - intracranial
• and others

Watch out for squinting and dullness in children!

It is very difficult to detect any visual impairment in childhood. For this reason it is also very important to have regular preventive check-ups with children.

Repeated eye exams are even more important for premature babies.

The child cannot express the fact that he has a vision problem. He may not even know it. He has perceived the world in an altered form since he was a child. He has no idea that reality is different.

The blurring of the image and the doubling of the image are examples.

But the brain can cope with a double image.

The human brain is plastic enough to cope with double vision.
Beware, however...
This compensation is not an ideal solution.

Why?

It solves the problem by turning off the image perception of the weaker eye.
Ultimately, the child may only see one object, but...

The consequence is impaired perception of surroundings, poor orientation in space, tripping, frequent falls or bumping into objects while walking, playing, running.

Why is this so?
The perception of 3D space allows us to capture the image of the world with both eyes.

This kind of compensation can be corrected up to a certain age, either by using an appropriate correction of the refractive error of the eye (glasses, occluders) or by correcting the squint. The ideal age is stated in the literature to be around 7 to 8 years of age. At a later age, the condition may be irreversible.

For more interesting information read the articles on:

1. squint
2. squinting
3. astigmatism

Double vision in pregnancy?

In this sensitive period for the woman and the fetus, there are occasional vision problems, either blurred or double vision. Of course, it is not good to neglect these changes.

One example is astigmatism, which can worsen during this period. It is reported that this happens in about one in five women who already suffered from astigmatism before becoming pregnant.

High blood pressure can also signal a complication, such as pre-eclampsia, which puts both the woman and the foetus at risk.

Beware!
Have vision problems suddenly arisen with no apparent cause?
This may be a life-threatening condition.
Seek professional help as soon as possible.
A doctor will check the mother and the unborn baby.

Read more in this article:
How to recognise pre-eclampsia and its symptoms in pregnancy? Know the risks

Diplopia voluntarily?

Yes. Some people induce it deliberately. And they do it as a form of fun or experiment, an example being the use of a stereogram. More skilful individuals can squint on force.

Try it out with us...

While reading our article, place one finger between the screen and your face. Focus on the text, not your finger.

Can you see it - diplopia?

What other symptoms may be present?

In addition to double vision itself, people complain of other difficulties and complications that accompany this condition.

Other difficulties that may be associated:

• Headache
• blurred, blurred vision
• eye pain and pain worsening with eye movement
• pain in the area around the eye
• tired eyes
• feeling of heavy eyelids
• increased watery eyes
• or, conversely, a feeling of dry eye
• photophobia/photophobia, i.e. an exaggerated sensitivity to light
• redness of the eyes and conjunctivae
• fatigue
• stress
• dizziness
• nausea, nausea or vomiting
• sore throat

Warning:
The combination of sudden to rapid onset of high intensity problems, such as intense to severe headaches and visual and double vision disturbances, raises red flags.

13. red flags for headaches:

1. The first headache in a person after the age of 40
2. Intense - severe pain
3. pain described as unlike anything one has ever experienced before.
4. change in the nature of the pain
   • the onset of new pain
   • significant increase in intensity
   • worsening headache
5. increasing pain intensity with vomiting
6. sudden onset of pain
7. sudden onset of pain after physical exertion (after coughing, after sneezing, after pressure on stool)
8. visual disturbance, even double vision
9. association of symptoms such as:
   • drowsiness, impaired consciousness, behavioral changes, confusion, disorientation
   • collapse
   • meningeal symptoms
   • fever
   • other neurological symptoms such as impaired mobility, weakness and paralysis of the limb
   • body spasms
10. headache after head and cervical spine injury
11. presence of cancer
12. blood medications, anticoagulant treatment, warfarin
13. HIV, AIDS

More about red flags in headache in the article:
Headache: Sometimes it is harmless, but when does it indicate a serious problem?
= Any visual impairment with associated symptoms that come on suddenly requires professional evaluation without delay.

How to diagnose?

The most important thing is information from the affected person, i.e. history. This is followed by an eye examination. This includes examination of the anterior and posterior segments, visual acuity and others.

Subsequently, the doctor may recommend X-ray, CT, MRI.

It is important to note that early diagnosis and early treatment in some cases has a significant impact on the final outcome.

Treatment is carried out according to...

Treatment can proceed after the cause is determined during diagnosis. Depending on this, a conservative or invasive approach is chosen (for example, in the case of a squint).

Examples are eye exercises (eye gymnastics for eye muscle dysfunction), correction with glasses or contact lenses or laser surgery, occluder overlay or correction of squint, surgical solution of cataract, etc.