Diplopia | Medical Council of Canada
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Version: March 2023
Legacy ID: 23


Diplopia, or double vision, refers to seeing two images of the same object at the same time. Diplopia can be caused by conditions affecting one eye (monocular) or both eyes (binocular). Diplopia may be of relatively benign etiology and easily correctable but may also be a symptom of more serious health issues.

Causal Conditions

(list not exhaustive)

  1. Monocular diplopia (e.g., refractive error, cataract)
  2. Binocular diplopia
    1. Oculomotor nerve dysfunction
      1. Ischemia
      2. Diabetes-associated
      3. Multiple sclerosis
      4. Intercranial mass (e.g., aneurysm)
    2. Myasthenia gravis
    3. Graves orbitopathy
    4. Orbital inflammation, infection, or tumour
    5. Fracture of orbital floor or “blow out”
    6. Decompensation of childhood phoria (e.g., squint)

Key Objectives

Given a patient with diplopia, the candidate will diagnose the cause and severity of diplopia and will initiate an appropriate management plan. Of particular importance is the clinical determination of whether true binocular diplopia is present, which resolves with occlusion of vision to either eye.

Enabling Objectives

Given a patient with diplopia, the candidate will

  1. list and interpret critical clinical findings, including
    1. indications of the underlying disease process (e.g., pain, features of hyperthyroidism);
    2. symptom onset and progression; and
    3. results of an appropriate physical examination (e.g., eyes, neurologic, thyroid);
  2. list and interpret critical investigations, including identifying underlying medical conditions; and
  3. construct an effective initial management plan, including determining whether the patient requires specialized care.