Last reviewed: 9 Nov 2022
Last updated: 14 Dec 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • infant not tracking parent's face
  • abnormal red reflex
More key diagnostic factors

Other diagnostic factors

  • asymptomatic
  • subnormal visual acuity for age in one or both eyes
  • asymmetric corneal light reflex
  • unequal behavioural response to alternate eye occlusion
  • abnormal cover/uncover testing
  • blurred vision
  • eye strain
  • congenital nystagmus
  • abnormal pupil exam
  • abnormal external eye exam
Other diagnostic factors

Risk factors

  • age <9 years
  • prematurity
  • family history of amblyopia or strabismus
  • strabismus (misalignment of the eyes)
  • hyperopic anisometropia (long-sightedness with unequal refractive error between the 2 eyes) of >+1.50 dioptre
  • myopic anisometropia
  • astigmatism (cylindrical, rather than spherical, defocus of the eye) >2.00 dioptre
  • hyperopia >+4.50 dioptre
  • myopia >-3.00 dioptre
  • opacity in the cornea, anterior chamber, lens, vitreous chamber, or retinal surface
  • severe ptosis or prolonged occlusion of one or both eyes
  • developmental delay
More risk factors

Diagnostic investigations

1st investigations to order

  • visual acuity tests (by specialist)
  • stereopsis (perception of depth or 3-dimensionality) and binocular vision testing
  • assessment of fixation, ocular alignment, and ocular motility
  • anterior segment examination using a slit lamp
  • dilated fundoscopy
  • cycloplegic retinoscopy
  • binocular red reflex test (Brückner test)
More 1st investigations to order

Emerging tests

  • visual evoked potentials

Treatment algorithm


without form-deprivation amblyopia

form-deprivation amblyopia

refractory amblyopia (non-compliant patient)



Irene Gottlob, MD

Professor of Ophthalmology

Department of Neuroscience, Psychology and Behaviour

University of Leicester

Ulverscroft Eye Unit

Leicester Royal Infirmary



IG has undertaken amblyopia research supported by the National Eye Research Centre, the Ulverscroft Foundation, the National Institute of Health Research, and Action Medical Research. An employer of IG, The University of Leicester, holds a European patent for glass dose monitors. IG is an author of references cited in this topic.

Gail Maconachie, PhD, BMedSci

Research Orthoptist

Department of Neuroscience, Psychology and Behaviour

University of Leicester



GM declares that she has no competing interests. GM is an author of a reference cited in this topic.


Dr Irene Gottlob and Dr Gail Maconachie would like to gratefully acknowledge Dr Tina Rutar, the previous contributor to this topic.


TR declared that she had no competing interests.

Peer reviewers

David Robbins Tien, MD

Associate Clinical Professor of Ophthalmology

Alpert Medical School of Brown University

Director of Ophthalmology

Hasbro Children's Hospital




DRT declares that he has no competing interests.

David K. Wallace, MD, MPH

Associate Professor of Ophthalmology and Pediatrics

Duke Eye Center




DKW has received NEI grants of more than 6 figures USD. DKW is an author of a number of references cited in this topic.

Michael Clarke, FRCS, FCOphth

Reader in Ophthalmology

Newcastle University




MC has received NHS research grants of more than 6 figures USD. MC is an author of a number of references cited in this topic.

  • Amblyopia images
  • Differentials

    • Refractive error with no amblyopia
    • Functional visual impairment
    • Central nervous system pathology affecting visual pathways
    More Differentials
  • Guidelines

    • Recommendations on vision defects screening in children
    • Vision in children ages 6 months to 5 years: screening
    More Guidelines
  • padlock-lockedLog in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer