Disease Description (Causes and Symptoms)
Diplopia is a symptom in which one object appears as two (or as a duplicated shadow). The causes are broadly divided into monocular diplopia and binocular diplopia.
- Monocular diplopia: A condition in which double vision occurs even when viewing with only one eye. Causes include corneal irregularity (keratoconus), astigmatism, lens dislocation, cataracts, pterygium, and ocular surface disease. Pathophysiologically, irregularities in the optical system (cornea and lens) cause two images to form or become distorted.
- Binocular diplopia: A condition in which the images formed by each eye do not correspond because of misalignment of the two eyes. Causes may include extraocular muscle problems (myositis or trauma), cranial nerve palsy (cranial nerves III, IV, and VI), myasthenia gravis, and central lesions such as stroke or tumors. Binocular diplopia is characterized by the symptoms disappearing when one eye is covered. Main symptoms: Objects appear overlapped or doubled in horizontal, vertical, or diagonal directions; tilting or turning the head; headaches, dizziness, and difficulty walking due to diplopia. In children, it may appear as eye rubbing, closing one eye, or tilting the head.
Treatment Methods
Treatment depends on the cause.
- Treatment of the cause
- Cataracts and pterygium: Improvement after surgical removal (cataract surgery or pterygium excision).
- Extraocular muscle injury/strabismus: Extraocular muscle surgery (strabismus surgery), prism treatment, and optical correction (glasses or contact lenses).
- Lens dislocation/astigmatism: Appropriate lens prescription and, in some cases, surgery.
- Myasthenia gravis (MG): Anticholinesterases (such as pyridostigmine), immunotherapy (immunoglobulin, steroids, and immunosuppressants), and thymectomy when necessary.
- Cerebrovascular disease/tumors: Vascular and neurological treatment (such as anticoagulation or thrombolysis), surgery, radiation therapy, and other treatments according to the neurological cause.
- Symptom relief
- Prism glasses: Relieve binocular diplopia by correcting misalignment of the eyes.
- Temporary protection using a monocular patch (eye patch) or prism: Helps prevent safety accidents and supports daily activities.
- Botox (botulinum toxin) injections: Used as an alternative or adjunctive treatment in some cases of strabismus and ocular motility disorders.
- Medications
- Inflammatory extraocular muscle inflammation and nerve inflammation: Steroids or immunosuppressants.
- Diabetic nerve palsy: Blood glucose control is essential (symptomatic treatment and observation over time).
- Lifestyle management and precautions
- Avoid driving, working at heights, and operating machinery while symptoms are present.
- Reduce the risk of falls (improve lighting and use assistive devices).
- Actively manage chronic diseases (diabetes and hypertension).
Checklist Before an Outpatient Visit (Including Example Questions)
Items and records to prepare:
- A list of currently used medications (including prescription drugs, nonprescription drugs, and supplements)
- When the symptoms began and their progression (sudden vs. gradual), which eye they began in, and whether they disappear when one eye is covered (to distinguish monocular from binocular diplopia)
- Positions that worsen the diplopia (e.g., tilting the head) and factors that temporarily improve it (e.g., using an eye patch or prism)
- Any recent trauma, head injury, eye surgery, history of infection, or systemic diseases (diabetes, hypertension, thyroid disease, or neuromuscular disease)
- Bring or record the results of any previous tests (ophthalmic or neurological examinations, CT/MRI, or blood tests)
- A photo or smartphone recording of what is seen when diplopia occurs, if possible
Examples of questions doctors frequently ask during the consultation:
- When did the diplopia begin? Did it develop suddenly?
- Do the symptoms disappear when one eye is covered?
- Does it worsen when you tilt your head or look in a particular direction?
- Have you recently had a severe headache, dizziness, or numbness in your speech or limbs?
Examples of General Questions to Ask the Doctor
- What is causing this diplopia? What additional tests are needed?
- What are the treatment options, their expected effects, and the expected treatment duration?
- Is it safe to drive or perform specific activities with my current diplopia?
- What are the side effects of the medications or the risks of surgery?
Examples of Disease-Specific Questions
- (If myasthenia gravis is suspected) What blood tests or electrophysiological tests (EMG) are needed to evaluate myasthenia gravis? When should immunotherapy be started?
- (If acute, sudden diplopia or nerve palsy is suspected) When should CT/MRI or vascular imaging (CTA/MRA) be performed to rule out cerebrovascular causes (stroke or aneurysm)?
Precautions and Prognosis
- Precautions
- Sudden diplopia, especially when accompanied by other neurological symptoms, requires emergency evaluation to rule out potentially fatal causes such as stroke or aneurysm.
- Avoid driving and operating dangerous machinery while symptoms are present.
- Diplopia in children can progress to reduced vision (amblyopia), so early diagnosis and treatment are important.
- Risk of complications
- Amblyopia (reduced vision in one eye) if left untreated for a long time in children.
- Falls, trauma, and reduced ability to perform daily activities.
- Neurological complications related to the underlying disease (such as stroke or tumor progression).
- Prognosis
- The prognosis depends on the cause: Improvement is possible after surgery for cataracts or pterygium, and diabetic nerve palsy often recovers spontaneously within several months with blood glucose control (usually 3–6 months). Cerebrovascular and neurological lesions vary depending on the cause and treatment. Myasthenia gravis may improve with appropriate immunotherapy, but relapses and a chronic course may occur.