Paeds · ophthalmology
Strabismus and ocular motility disorders
Also known as Squint · Misalignment of the visual axes · Esotropia · Exotropia · Childhood strabismus · Comitant and incomitant deviation · Cranial nerve palsy in children · Amblyopia and ocular misalignment
Fellowship topic on strabismus and ocular motility disorders in children: the definition of strabismus as a misalignment of the visual axes and the comitant-versus-incomitant fork that drives investigation; the cover-uncover and alternate-cover tests and the prism and Hirschberg methods for quantifying a deviation; the classification of horizontal deviations into infantile esotropia, accommodative esotropia (refractive and high accommodative convergence to accommodation ratio needing bifocals), acute acquired comitant esotropia as a red flag for intracranial disease, pseudoesotropia from epicanthal folds, and intermittent exotropia with its divergence-excess and convergence-insufficiency patterns; the incomitant disorders of cranial nerve three, four and six palsy, Duane retraction and Brown syndromes, restrictive disease from orbital fracture, and childhood myasthenia; the pathophysiology of suppression, anomalous retinal correspondence and amblyopia that follows childhood misalignment within the critical period of roughly the first seven years; the stepwise management of cycloplegic refraction then refractive correction then amblyopia therapy (occlusion or atropine penalisation) before any surgery, with prism, overminus lenses and botulinum toxin for selected deviations and recession or resection surgery timed to binocular potential; the red flags that demand neuroimaging and urgent referral; and the ANZ and international ophthalmology and primary-care guidance.
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Target exams
Red flags
- An older child with new, acute comitant esotropia and no significant refractive error — possible intracranial pathology; urgent neuroimaging and neurological assessment rather than simply listing for strabismus surgery
- Any incomitant deviation, especially a new cranial nerve palsy (third, fourth or sixth) with diplopia, ptosis, pupillary change, head tilt or weakness — image and refer urgently; a sixth nerve palsy can reflect raised intracranial pressure
- A painful third nerve palsy with a dilated pupil in a child — possible compressive lesion; treat as an emergency and image immediately
- A child with strabismus who has never had a refraction or who has a sensory deviation from undiagnosed poor vision — find and treat the cause of the poor vision, including a dilated fundus examination to exclude retinoblastoma, cataract or optic nerve disease
Life stages
Care settings
Clinical exam formats
Board mappings
- General and Community Paediatrics: vision and ocular-alignment screening, the cover test, the referral threshold to ophthalmology, and recognition of the red flags for intracranial disease
- Growth and Development: amblyopia and the critical period of visual development; why early alignment and refractive correction protect binocular vision
- Neonatal and infant: recognition of congenital or infantile strabismus and the importance of a red-reflex and dilated fundus examination to exclude sensory causes
- Ophthalmology: comitant versus incomitant strabismus, the ocular-motility examination, cycloplegic refraction and the amblyopia-first management sequence
- Neurology and neurodisability: cranial nerve three, four and six palsies, raised intracranial pressure, Duane and Brown syndromes, and childhood myasthenia
- Renewed curriculum for first-year trainees from 2027 — Learning goal: essential general paediatrics, including timely detection and referral of childhood visual disorders
- General/Community 10-12: vision screening, the cover-uncover and alternate-cover tests, pseudoesotropia, and when to refer to ophthalmology
- Ophthalmology 10-12: the common horizontal deviations, amblyopia therapy principles and the red flags for urgent referral
- Clinical Applications: the stepwise management of a child with a turned eye and the communication of amblyopia treatment to a family
- Short case: examine a child's ocular alignment and ocular motility, demonstrate the cover test and discuss your differential and plan
- Long case / structured discussion: a child with infantile or accommodative esotropia, or with intermittent exotropia — diagnosis, amblyopia management, surgical timing and prognosis
- Communication station: explaining amblyopia patching or atropine penalisation and the rationale for surgery to a family
- Level 2 / 3 — Ophthalmology: assessment of ocular alignment and motility, recognition of amblyopia risk and timely referral
- 1. Neonates and infants: detection of congenital strabismus and exclusion of sensory causes through red-reflex and fundus examination
- Neurodisability: ocular-motility disorders in cerebral palsy, Down syndrome and neurogenetic conditions
- Foundation of Practice (FOP): normal visual development, the cover test, pseudoesotropia and the common childhood deviations
- Applied Knowledge in Practice (AKP): amblyopia and its treatment, the comitant-versus-incomitant distinction and the red flags for neuroimaging
- Clinical: examining ocular alignment and ocular motility and demonstrating the cover test
- History-taking and management: a child with a turned eye, including amblyopia therapy and the rationale and timing of surgery
- Communication: explaining patching or penalisation and the prognosis to a family
- General Pediatrics Content Outline — ophthalmology: ocular alignment, the cover test, amblyopia and referral criteria
- Neurology: cranial nerve palsies and raised intracranial pressure presenting as incomitant strabismus
- Universal Task 4: Management and treatment — the amblyopia-first, refractive-correction-first sequence
- Patient Care: detection of strabismus and amblyopia, performance of the cover test, and timely referral
- Medical Knowledge: comitant versus incomitant strabismus, the pathophysiology of amblyopia, and the cranial nerve palsies
- Systems-Based Practice: vision-screening pathways and equitable access to paediatric ophthalmology for rural and remote families
- Medical Expert: diagnosis and stepwise management of childhood strabismus and amblyopia across the comitant and incomitant spectrum
- Collaborator and Health Advocate: coordinated ophthalmology, orthoptic and primary-care care and equitable access for underserved communities
- Communicator: explaining amblyopia therapy and surgical rationale to children and families
Two children with a turned eye — and a very different plan
Accommodative esotropia (comitant)
New sixth nerve palsy (incomitant)
The cover-uncover test catches the manifest deviation — the tropia. Cover one eye and watch the other: if the uncovered eye flicks out to take up fixation, that eye had a tropia. The alternate-cover test breaks fusion and unmasksthe hidden latent deviation — the phoria — and the total deviation, so it always measures more than the cover-uncover test. Put a prism in front to bring the refixation movement to a stop and you read the angle in prism dioptres. When no child will cooperate, fall back on the Hirschberg corneal-reflex test: each millimetre that the reflex sits off centre is roughly seven degrees or about fifteen prism dioptres. [1] [12]
Overview & Definition
Picture a four-month-old brought in because the eyes have crossed since birth, a three-year-old who screws up one eye in bright sunlight, and a seven-year-old who has started seeing double. Each story is strabismus, yet the meaning of the turn could not be more different: the first is a developmental deviation to align and salvage binocular vision, the second is intermittent exotropia that may deteriorate, and the third is a red flag for a cranial nerve problem. The same sign — eyes not pointing together — opens three completely different clinical paths. [1] [6]
Strabismus is a misalignment of the visual axes, so the two foveas no longer look at the same object at the same time. We name it by direction — esotropia (inward), exotropia (outward), hypertropia (one eye up) and hypotropia (one eye down) — and we separate the manifest deviation, the tropia, from the latent one, the phoria, that only appears when fusion is broken. The other axis that matters most is whether the angle stays constant in every direction of gaze (comitant) or changes as the eyes move (incomitant), because that distinction routes the child toward either routine paediatric ophthalmology or urgent neurology. [1] [3]
The clinician's task runs in three layers. The first is detection and measurement: perform the cover test, quantify the angle, and decide comitant versus incomitant. The second is the management sequence: cycloplegic refraction, refractive correction, amblyopia therapy, then alignment through prism, overminus lenses, botulinum toxin or surgery. The third is vigilance — recognising that a sensory deviation may hide retinoblastoma or a cataract, and that acute or incomitant strabismus may hide a brain lesion. Strabismus is common and often benign, but it rewards a methodical, cover-test-led approach. [1] [12]
References12ShowHide
- [1]Donahue SP Clinical practice. Pediatric strabismus. N Engl J Med, 2007.PMID 17347457
- [2]Hutchinson AK; Morse CL; Hercinovic A; et al Pediatric Eye Evaluations Preferred Practice Pattern. Ophthalmology, 2023.PMID 36543602
- [3]Mocan MC; Pastapur A; Kaufman L Etiology-based strabismus classification scheme for pediatricians. Turk J Pediatr, 2022.PMID 35611422
- [4]Mehner L; Ng SM; Singh J Interventions for infantile esotropia. Cochrane Database Syst Rev, 2023.PMID 36645238
- [5]Lembo A; Serafino M; Strologo MD; et al Accommodative esotropia: the state of the art. Int Ophthalmol, 2019.PMID 29332227
- [6]Campos EC Why do the eyes cross? A review and discussion of the nature and origin of essential infantile esotropia, microstrabismus, accommodative esotropia, and acute comitant esotropia. J AAPOS, 2008.PMID 18550403
- [7]Pang Y; Gnanaraj L; Gayleard J; et al Interventions for intermittent exotropia. Cochrane Database Syst Rev, 2021.PMID 34516656
- [8]Chen AM, Erzurum SA, Chandler DL, et al. Refractive Error Change and Overminus Lens Therapy for Childhood Intermittent Exotropia. JAMA Ophthalmol, 2024.PMID 38536764
- [9]Pediatric Eye Disease Investigator Group A randomized trial of atropine vs. patching for treatment of moderate amblyopia in children. Arch Ophthalmol, 2002.PMID 11879129
- [10]Li T; Qureshi R; Taylor K Conventional occlusion versus pharmacologic penalization for amblyopia. Cochrane Database Syst Rev, 2019.PMID 31461545
- [11]Holmes JM; Clarke MP Amblyopia. Lancet, 2006.PMID 16631913
- [12]Reedy-Cooper A; Scartozzi C; Yurkonis T Childhood Eye Examination in Primary Care. Am Fam Physician, 2023.PMID 37440736