What is diplopia?
Diplopia is defined as seeing two images of a single object when you’re looking at it. Double vision is usually a temporary issue, but it can also be a sign of more serious health conditions.
2. What are the types of diplopia?
There are two types of diplopia, they are monocular diplopia (affects one eye) and binocular diplopia (affects both eyes).
3. What is the difference between binocular and uniocular diplopia?
In binocular diplopia, the double vision resolves with either one of the eye covered. In monocular diplopia, the double vision disappears when the affected eye is covered.
4. What is the most common cause of monocular diplopia?
Common causes include uncorrected astigmatism, corneal irregularities, tear film abnormalities, cataract, etc. The hallmark of monocular diplopia from refractive abnormalities is improvement with pinhole. Rarely, cerebral monocular diplopia is bilateral and rare.
5. What diseases cause binocular diplopia?
They include neurological conditions, such as myasthenia gravis or multiple sclerosis, or may be associated with a systemic disorder, such as hyperthyroidism. Double vision can also be a symptom of a stroke, an aneurysm, or head or facial trauma, especially around the eye socket.
6. Is diplopia a serious condition?
Depends on the presentation of diplopia, whether the onset of double vision recent (which may indicate a neurological event) or long-standing (decompensated strabismus, which is less urgent).Patients may recall an antecedent event such as head trauma, cerebrovascular event or sinus surgery.
Diplopia, especially of acute onset, is a red flag and the possibility of an underlying neurological cause should be strongly considered.
7. What are the other complaints encountered in a patient with diplopia?
- Are the images separated horizontally (suggesting decompensated divergent or convergent squint, sixth nerve palsy, or internuclear ophthalmoplegia secondary to multiple sclerosis) or vertically (suggesting third and fourth nerve palsy or restrictive disorders such as blow out fracture or thyroid eye disease)
- Are there any associated symptoms such as ptosis (third nerve palsy, myasthenia)
- Blurred vision (third nerve palsy due to dilated pupil)
- Headache (raised intracranial pressure)
- Weakness, fatigue, or difficulty in swallowing (myasthenia, demyelinating disorders),
- Oscillopsia (due to nystagmus in internuclear ophthalmoplegia),
- Lid retraction or proptosis (thyroid eye disease),
- Temporal headache and pain while swallowing (temporal arteritis or giant call arteritis [GCA]) or abnormal head posture.
8. How will you assess diplopia?
- Meticulous history taking including previous h/o glasses/CL with or without prisms ,amblyopia, eye trauma, refractive or strabismus sx
- A family history of strabismus, amblyopia and high refractive errors may signify a genetic component.
- Screen for systemic conditions like DM, HTN,hyperthyroidism, myasthenia or any drug intake
- Comprehensive eye exam, inclusive of visual acuity,pupil involvement, EOM, assessment of degreeof strabismus,anterior segment and fundus evaluation.
- A fixed dilated pupil associated with headache and diplopia is a neurosurgical emergency and necessitates urgent imaging,MRI.
9. Any neurological evaluation needed?
All patients with diplopia should undergo a full cranial nerve and peripheral nervous system examination, as multiple cranial nerve palsies may signify intracranial- or meningeal-based tumours, meningitis, polyneuropathy, multiple sclerosis or cavernous sinus lesion.
10. What are the investigation you perform in a patient with diplopia?
It is helpful to measure blood pressure and blood glucose and carry out an urinalysis for suspected microvascular cases, thyroid function tests, or single fibre EMG of the orbicularis and anti-acetylcholine receptor antibodies for myasthenia.
Imaging (an MRI or CT angiography scan) may be indicated if the onset is acute and/or associated with neurological signs or papilloedema.
11. How will you manage a case of diplopia?
All patients with new-onset diplopia should be advised to stop driving.Most microvascular causes of diplopia can be observed if the rest of the examination is normal as they usually spontaneously resolve within 6 months. They may benefit from referral to the ophthalmology department as the diplopia can be alleviated with prisms, patches or toxin in the meantime.
Urgent, same-day imaging should be sought for patients with a fixed dilated pupil, headache and diplopia. An acute medical or rheumatology referral should be made if there is suspicion of associated GCA. Other symptoms of GCA include loss of weight, night sweats, temporal headache, jaw claudication and visual loss.
