Double Vision

Double vision, or diplopia, can be a troublesome and sometimes alarming symptom. It occurs when a person sees two images of a single object. This eye problem affects people of all ages and impacts daily activities, from reading to driving. Double vision has various causes, ranging from minor eye muscle imbalances to serious underlying health conditions. This article explores the symptoms, reasons for double vision, and potential treatments.

What is Double Vision (Diplopia)? 

Diplopia (Double vision), medically known as diplopia, occurs when a person sees two images of a single object, either side by side or overlapping. This visual disturbance impacts daily activities and can be quite unsettling for those experiencing it. 

Diplopia (Double vision) is classified into two main categories: 

• Monocular Diplopia: This type affects only one eye and persists even when the unaffected eye is covered. It often appears as a shadow or ghost image alongside the main image. This type of double vision is generally less severe and more common than its counterpart. 
• Binocular Diplopia: Occurs when both eyes are open and disappear when one eye is covered. It results from the misalignment of the eyes, preventing them from working together properly. Binocular diplopia is usually considered more serious as it can indicate underlying health conditions affecting eye muscles or nerves. 

Causes of Diplopia (Double Vision)

Diplopia can stem from various conditions affecting the eyes, muscles, nerves, or brain. Several diseases that cause double vision range from minor issues to potentially life-threatening conditions. 

• Eye-Related Causes: Corneal Problems: The cornea, the eye's clear front surface, can cause double vision when distorted. Common issues include: 
  • Astigmatism 
  • Dry eyes 
  • Infections (e.g., shingles or herpes zoster) 
  • Scars from disease, injury, or infection 
• Lens Issues: The most frequent lens-related cause is cataracts, a clouding of the usually clear lens due to ageing. Other causes are: 
  • Nearsightedness (myopia) 
  • Farsightedness (hyperopia) 
  • Poorly-fitting glasses or contact lenses 
  • Other Eye Conditions: 
  • Keratoconus 
  • Abnormalities in the iris 
• Muscle and Nerve-related Causes of Double Vision: Extraocular Muscle Problems: These muscles control eye movement. Issues can include: 
  • Graves' disease 
  • Strabismus 
• Cranial Nerve Disorders: Certain conditions can damage the nerves controlling eye movement, such as: 
  • Diabetes 
  • Guillain-Barré syndrome 
  • Myasthenia gravis 
  • Multiple sclerosis 
  • Brain-related Cause of Double Vision: 
• Several brain conditions can lead to double vision by affecting areas that process visual information: 
  • Brain aneurysm 
  • Brain tumour 
  • Migraine headaches 
  • Increased intracranial pressure from bleeding, infection, or trauma 
  • Stroke 
  • Other Causes: 
  • Giant cell arteritis (Temporal Arteritis) 
  • Head injuries 
  • Proptosis (Bulging eyes) 

Double Vision (Diplopia) Symptoms

Diplopia can affect one eye or both eyes. The primary symptom of diplopia is seeing two images of a single object. These images may appear side by side, one on top of the other, or slightly slanted. The clarity of these images can vary; sometimes, both are clear but misaligned, while in other cases, one image may be blurry and the other clear. 

In addition to the doubled vision, individuals experiencing diplopia may notice several accompanying symptoms: 

• Headache 
• Nausea or feeling sick 
• Dizziness 
• Eye pain, especially when moving the eyes 

Diagnosis of Double Vision 

Eye care specialists (Ophthalmologists) play a crucial role in diagnosing double vision and determining the underlying cause of double vision. The diagnostic process begins with a comprehensive eye examination and a visual acuity test. These initial assessments help the specialist understand the nature and severity of the double vision. 

During the examination, the doctor asks several key questions to gather essential information: 

• Does the double vision occur with both eyes open or only one? 
• Does closing one eye make the double image disappear? 
• Is the double image horizontal or vertical? 
• How severe are the symptoms, and how long have they been present? 
• Are there any factors that worsen or alleviate the double vision? 
• Does the patient have any relevant medical conditions, such as diabetes or vertigo? 
• Has the patient experienced any recent head trauma or concussion? 

Physical Assessment: 

The doctor may conduct a series of painless tests to evaluate eye alignment and muscle function. These include: 

• Prism Test: This test measures the degree of eye misalignment. 
• Eye Movement Test: This test helps assess eye muscle weakness and identify any issues with eye movement. 
• Slit Lamp Examination: The doctor uses a slit lamp to examine the eye's internal structures under magnification. 
• For a more comprehensive evaluation, the doctor may recommend further diagnostic tests: 
• Magnetic Resonance Imaging (MRI): This imaging technique helps rule out conditions such as tumours, nerve inflammation, or aneurysms. 
• Computed Tomography (CT) Scan: This test offers detailed images of bones, muscles, and surrounding structures, aiding in identifying issues that might cause double vision. 
• Blood Tests: These are useful in detecting underlying medical conditions like Graves' disease or Lyme disease, which can contribute to double vision. 

Treatment of Double Vision 

The double vision treatment depends on its underlying cause. Eye care specialists tailor the approach to each patient's specific condition, ranging from simple solutions to more complex interventions. 

Eye specialists will recommend one or more of the following treatments: 

• Vision Blocking or Blurring: 
  • Eye patch 
  • Occlusive lens (contact lens or applied to glasses) 
  • Fresnel prism applied to glasses 
• Botulinum Toxin (Botox) Injections: Doctors inject Botox into the stronger eye muscle to relax, allowing the weaker eye muscle to recover. 
• Prism Therapy: Prisms in glasses help to realign images from each eye. They can be stick-on (temporary) or permanently ground into the lenses. 
• Surgery: In less common cases, surgery may be necessary to treat muscular problems affecting eye alignment. 
• Vision Therapy: This therapy can be beneficial for conditions like convergence insufficiency. This therapy includes eye exercises prescribed by optometrists to develop or improve visual skills. 
• Treating Underlying Medical Conditions: In cases where double vision stems from other health issues, coordinated care with various specialists becomes crucial. 

When to See a Doctor 

Diplopia (Double vision) can be a concerning symptom that requires prompt medical attention. Eye care specialists emphasise the importance of seeking professional help when an individual notices changes in their vision. 

Individuals should visit an eye care specialist immediately if they experience: 

• Persistent double vision 
• Sudden onset of double vision 
• If other symptoms accompany double vision, such as eye pain, dizziness, muscle weakness, slurred speech, or confusion 

Prevention 

While it's not always possible to prevent double vision entirely, individuals can take proactive steps to maintain good eye health and identify potential issues early. To maintain optimal eye health and potentially prevent double vision, people should: 

• Schedule regular eye evaluations every one to two years, or as often as recommended, to help detect and address vision issues early. 
• Wearing appropriate protective glasses or goggles during work, sports, or hobbies safeguards the eyes from potential injuries that could lead to vision problems. 
• Giving the eyes regular breaks from electronic screens throughout the day helps reduce eye strain and fatigue. 
• Quitting or avoiding smoking can help maintain good vision. 
• Practising good eye hygiene and avoiding rubbing them can prevent infections and irritations that might affect vision. 
• A balanced diet rich in vitamins A, C, and E and omega-3 fatty acids supports eye health. 
• Proper hydration helps maintain natural eye moisture, preventing dryness and discomfort. 
• Managing underlying health conditions helps prevent complications that affect vision. 
• Practising eye exercises may prove beneficial; these include: 
• Smooth Convergence: This involves focusing on a small object as it moves closer to the nose, helping the eyes work together more effectively. 
• Jump Convergence: This exercise requires quickly shifting focus between a distant and close object, improving the eyes' ability to adjust rapidly. 

Conclusion 

Double vision can significantly impact daily life, affecting reading and driving activities. This visual disturbance stems from various causes, ranging from minor eye muscle imbalances to serious health conditions. Understanding the symptoms and potential causes helps individuals recognise when to seek medical attention, which is crucial for early diagnosis and treatment. By working closely with doctors and following recommended treatments, many people with double vision can find relief and improve their quality of life. 

FAQ's 

1. Who does double vision (diplopia) affect? 

Double vision, or diplopia, affects a wide range of individuals. It's a common visual disturbance that impacts people of all ages. This condition does not discriminate based on age or gender, as it stems from various underlying causes that can affect anyone. 

2. How common is diplopia? 

Diplopia is quite prevalent. Seek professional help for double vision each year. 

3. What does it look like to see double? 

When a person experiences double vision, they see two images of a single object instead of one. The appearance of these doubled images can vary: 

• The images may overlap or be separate. 
• They might appear tilted or straight. 
• In some cases, it's a combination of these effects. 

Some people describe the experience as seeing a fainter "ghost image" alongside the main image. 

4. How can I stop double vision? 

Stopping double vision depends on its underlying cause. Eye care specialists recommend various treatments based on the specific condition, such as correct, adjusted glasses or contact lenses, eye exercises, blocking or blurring vision in one eye using an eye patch or occlusive lens, botulinum toxin (Botox) injections into the stronger eye muscle, treating underlying systemic conditions, or in severe cases, surgery for some muscular issues. 

5. What deficiency causes double vision? 

Several vitamin deficiencies have an association with double vision: 

• Vitamin B1 (Thiamine) deficiency 
• Vitamin B12 deficiency 
• Vitamin C deficiency 
• Zinc deficiency 
• Other factors include eye muscle problems, neurological conditions, and various systemic diseases.

Dr. Neelu Agrawal

CARE Medical Team

1