Double vision, also known as diplopia, is a visual impairment where a person sees two images of a single object. This can occur in one eye (monocular diplopia) or both eyes (binocular diplopia) and the images can appear vertical, horizontal or diagonal to each other.
This condition can be disorientating and affect one’s quality of life. Understanding the causes, diagnostic procedures and treatment options is crucial for effectively managing and alleviating double vision.
Monocular Diplopia
This occurs when double vision is present in just one eye. To test this, cover one eye, and if you still experience double vision, you have monocular diplopia in the opened eye. Common causes include:
- Refractive errors: eg., uncorrected myopia or astigmatism, requiring spectacle wear
- Corneal problems: eg., irregularity, scarring, swelling
- Lens problems: eg., cataract, dislocated lens
Binocular Diplopia
This occurs when double vision is present when both eyes are open and disappears when one eye is closed. It is typically due to problems with the alignment or movement of the eyes, and may arise from any part of the eye movement pathway such as:
- Brain – Stroke, trauma or brain tumours can affect areas of the brain that control eye movements
- Cranial nerve – Nerves that help the eye move can suffer temporary or permanent disruptions due to
- Diabetes
- Stroke
- Tumour
- Trauma
- Aneurysm
This may be accompanied by other symptoms, such as a droopy eyelid on the affected side
- Nerve-muscle junction – Myasthenia gravis is an autoimmune condition whereby antibodies attack the nerve-muscle junction. Ocular myasthenia gravis occurs when the muscles around the eye are affected, and may lead to double vision and/or droopy eyelids (ptosis). Symptoms are usually better in the morning, after a good night’s rest, and worsen throughout the day as the muscles fatigue easily.
- Muscle – Thyroid eye disease can cause swelling or inflammation in the eye muscles, affecting their function and causing diplopia
- Orbit (eye socket) such as
- Infection or inflammation
- Orbital wall fracture due to trauma. Blunt force injury to the eye can cause the bony structures that encase the eye to break, leading to tissues, including eye muscles, being trapped.
- Tumour
Diagnosis of Double Vision
If you experience double vision, it’s essential to see an ophthalmologist to determine the underlying cause. Diagnosis typically involves:
- Medical History – The eye doctor will review your medical history, including any recent injuries, illnesses or medications.
- Eye Examination – A thorough eye exam will assess visual acuity, eye alignment and the movement of the eyes.
- Neurological Examination – Since some causes of double vision are related to neurological issues, a neurological exam may be conducted to evaluate nerve function.
- Imaging Studies – Depending on the suspected cause, imaging tests such as CT scans, MRIs, or X-rays may be ordered to visualise the brain, eye muscles or orbit.
- Blood Tests – In some cases, blood tests may be performed to check for underlying conditions such as autoimmune disorders, hyperthyroidism or infections.
Treatment Options for Double Vision
Treatment for double vision depends on its underlying cause:
- Corrective Lenses – For refractive errors, corrective lenses may resolve the double vision.
- Prism Glasses – These special glasses can help align the images seen by each eye, alleviating the symptoms of diplopia.
- Eye Exercises – For conditions like strabismus, eye exercises or vision therapy might help improve eye alignment.
- Medication – Treating underlying conditions such as thyroid disease or myasthenia gravis with appropriate medication can help alleviate double vision.
- Surgery – In some cases, surgical intervention may be necessary to correct eye misalignment or to repair damage to the eye muscles or nerves.
Conclusion
Double vision can be a challenging and disturbing condition, but understanding its causes and seeking appropriate treatment can significantly improve quality of life. If you experience double vision, it’s important to consult with an eye care professional to determine the cause and receive proper treatment. Early diagnosis and intervention can often prevent complications and provide relief from this visual disturbance.