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Liying Low, Waqaar Shah, Caroline J MacEwen
Correspondence to: L Low firstname.lastname@example.org
What you should cover
Double vision, or diplopia, may be the first sign of life threatening pathology, or it may be completely benign. A rapid and systematic assessment is, therefore, crucial.
– Is the diplopia [monocular] or binocular? The latter may indicate a life threatening cause[.]
Monocular—Diplopia persists when one eye is covered. “What does the extra image look like?” The extra image typically appears as a ghost or shadow. Generally indicates abnormalities of the eye itself, including dry eyes, corneal pathology or scarring, cataracts, and non-organic causes.
Binocular—Diplopia occurs with both eyes open and disappears when either eye is covered.
- Are the images separated vertically (on top of each other), or horizontally (side by side)? Vertical diplopia indicates impaired elevation or depression of the eye (such as decompensated squints, thyroid eye disease, fourth nerve palsies, orbital trauma), whereas horizontal diplopia suggests impaired adduction or abduction of the eye (such as decompensated squints, sixth nerve palsies, multiple sclerosis).
- Is the double vision constant, intermittent, or variable? Patients with intermittent diplopia should be asked about timing, duration, and frequency of symptoms, and exacerbating and relieving factors. Intermittent diplopia worse in the evenings or with fatigue suggests myasthenia gravis or decompensating squint. Diplopia worse with spectacle prescription change suggests an accommodative or spectacle induced cause (both benign).
- Is the double vision worse with any particular direction of gaze?
– Onset of symptoms—Sudden onset of diplopia usually indicates acute aetiology, such as ischaemia or vascular compression. Gradual or intermittent onset may indicate decompensation of a latent or longstanding squint. Vague onset may be seen in thyroid eye disease.
– Associated features—Are there any associated headaches or pain around the eyes? May indicate ischaemia, inflammation, infection, raised intracranial pressure, or aneurysm.
– Weakness or fatigue—Is there any associated weakness or fatigue, particularly in the evenings, droopy eyelids, or difficulty swallowing? Possible myasthenia gravis.
– Trauma—Is there any recent head or facial trauma? Blow-out orbital fractures may cause extraocular muscle entrapment or damage.
– Other features—Is there any new onset headache, scalp tenderness, unexplained weight loss, or pain when chewing? Possible giant cell arteritis.
– Ocular history—Childhood squint or amblyopia, eye muscle surgery, or new glasses may suggest a longer term aetiology.
– Medical history—Diabetes, hypertension, and vasculopathic risk factors are associated with cranial nerve microvascular ischaemia. Include history of thyroid disease, cancer, and multiple sclerosis.
– Drug history—Drugs such as lamotrigine, topiramate, gabapentin, fluroquinolones, and citalopram have been associated with diplopia, but it is a rare adverse effect.
– Observe any abnormal head position (tilt or face turn) and compare with old photographs, which would support a longstanding problem.
– Observe the eyelid position—Ptosis of the upper eyelid may indicate third nerve palsy or myasthenia gravis, lid retraction may indicate thyroid eye disease.
– Inspect for strabismus (misalignment of the eyes)—For example, in third nerve palsy the affected eye turns “down and out”.
– Inspect for proptosis (protrusion of the eyeball)—Suggests orbital cellulitis, orbital tumours, thyroid eye disease, or carotid cavernous fistula.
– Is the [diplopia] monocular or binocular?—Cover each eye in turn and ask if the diplopia persists with either eye covered.
– Assess visual acuity in each eye—Longstanding reduced vision in one eye suggests amblyopia, while new onset reduced vision suggests orbital or neurological lesion.
– Pupil size and responses—A unilateral dilated pupil in association with headache and diplopia highly suggests an intracranial aneurysm (third nerve palsy), a neurosurgical emergency. Unilateral lid ptosis with pupillary miosis and unilateral cranial nerve palsies suggests Horner’s syndrome secondary to cavernous sinus pathology. These are red flag signs.
– Examine eye movements in nine positions of gaze—Ask if double vision worsens with different positions of gaze.
– Cranial nerve and peripheral nervous system examination should be completed in all cases of suspected extraocular muscle weakness. Multiple cranial nerve palsies indicate intracranial or meningeal based tumours, meningitis, polyneuropathy, multiple sclerosis, or cavernous sinus lesion.
– Papilloedema must be excluded in all cases of sixth nerve palsy (reduced abduction) as it can be a false localising sign of increased intracranial pressure.
What you should do
– Advise patients with diplopia not to drive.
Urgent, same day referral
– Painful third nerve palsy with ipsilateral dilated pupil or sixth nerve palsy with papilloedema—Refer to either acute medical or neurosurgical team for same day neuroimaging.
– Suspected giant cell arteritis—Refer to either the rheumatology or acute medical team or the ophthalmology team for urgent tests (including erythrocyte sedimentation rate and C reactive protein) and high dose corticosteroid treatment.
– Acute onset diplopia associated with facial trauma—Refer to the maxillofacial or ophthalmology team.
– Red flag symptoms need referral to the acute medicine or ophthalmology team.
Routine referral to ophthalmology department
– Any painless monocular diplopia or longstanding diplopia.
– Isolated fourth and sixth cranial nerve palsies. They should have cardiovascular risk factor work up.
– Suspected thyroid eye disease. They should have thyroid function tests performed and be advised to stop smoking.
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