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Practice Practice Pointer

Assessment of diplopia in adults

BMJ 2024; 385 doi: (Published 23 April 2024) Cite this as: BMJ 2024;385:e076413
  1. Twishaa Sheth, ophthalmology registrar1,
  2. Maneeta Morarji, head orthoptist2,
  3. Imran Jawaid, consultant ophthalmologist specialising in paediatric ophthalmology and strabismus3
  1. 1Colchester Hospital, East Suffolk & North Essex NHS Foundation Trust, Colchester, UK
  2. 2Milton Keynes University Hospital NHS Foundation Trust, Milton Keynes, UK
  3. 3Ophthalmology, Nottingham University Hospitals NHS Trust, Nottingham, UK
  1. Correspondence to: T Sheth twishaa.sheth1{at}

What you need to know

  • For a patient with double vision, differentiating between monocular and binocular diplopia can help guide the urgency of onward management

  • In an acute setting, for a patient with binocular diplopia and limited eye movements, the main differentials of concern are third, fourth, and six cranial nerve palsies. These should be urgently excluded

  • Clinicians must be aware of legal driving standards for patients with diplopia

Double vision, or diplopia, may be the first sign of sight or life threatening pathology. A thorough, accurate first assessment is important for determining the clinical urgency of related pathology and ensuring timely management.

Monocular or binocular diplopia?

Whether diplopia is monocular or binocular will help identify aetiology and determine the urgency of management. Ensure double vision is distinguished from blurred vision (when a patient sees a single image that appears unclear), which has many other distinct causes. In diplopia, the second image may appear fainter as a “ghost” image.

Monocular diplopia refers to double vision originating solely from one eye. This will persist when the patient is asked to cover the other, unaffected eye and suggests an intraocular pathology. Differentials for monocular diplopia include refractive error, dry eye syndrome, corneal pathology, cataract, and non-urgent retinal pathology. In such cases, a routine optometrist or ophthalmology referral is appropriate for further evaluation.

Binocular diplopia is double vision present with both eyes open that resolves on covering either eye, and is more commonly encountered.1 This symptom is usually more serious as it indicates misalignment of the eyes, secondary either to ocular muscle pathology or a central neurological cause.2 Patients presenting acutely with this symptom should therefore be referred urgently for ophthalmic assessment and worked up appropriately. Some patients may experience monocular diplopia bilaterally, which can be misinterpreted as binocular diplopia. Notably, bilateral monocular diplopia will remain present when each eye …

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