Double Vision (Diplopia)

What is Double Vision (Diplopia)?

Double vision, medically known as diplopia, is the perception of two images of a single object. These images may be side by side, one on top of the other, or a mixture of both. It can affect one eye (monocular) or both eyes (binocular).

Types of Double Vision

• Monocular Diplopia: Double vision that persists in one eye even when the other eye is covered. This is usually caused by an issue within the eye itself, such as a cataract, astigmatism, or dry eye.
• Binocular Diplopia: Double vision that only occurs when both eyes are open and disappears when either eye is covered. This indicates a misalignment of the eyes, often due to problems with the eye muscles or the nerves controlling them.

Common Causes

Monocular Causes:

• Cataracts (clouding of the lens)
• Dry eye syndrome
• Astigmatism or other refractive errors
• Corneal irregularities (e.g., keratoconus)

Binocular Causes:

• Strabismus (squint or turned eye)
• Cranial nerve palsies (damage to nerves controlling eye muscles)
• Thyroid Eye Disease
• Myasthenia gravis
• Neurological conditions (e.g., multiple sclerosis, stroke, brain tumor)
• Trauma to the eye muscles or orbit

When to Seek Immediate Medical Attention

Double vision can sometimes be a symptom of a serious underlying medical condition. Seek immediate emergency care if your double vision is accompanied by:

• Severe headache
• Weakness or numbness in your face or body
• Difficulty speaking or slurred speech
• Dizziness or loss of balance
• Drooping eyelid (ptosis)
• Pain when moving your eyes

Diagnosis and Treatment

An ophthalmologist will perform a comprehensive examination to determine the cause of your double vision. Treatment depends entirely on the underlying cause and may include:

• Corrective Lenses: Glasses with special prisms to align the images.
• Eye Exercises: Vision therapy for certain types of muscle weakness.
• Medications: To treat underlying conditions like myasthenia gravis or thyroid disease.
• Surgery: To correct eye muscle misalignment or remove cataracts.
• Botox Injections: To temporarily weaken an overactive eye muscle.