Summary

• A visual impairment resulting from abnormal visual stimulation during early childhood, the prevalence of which ranges from 1% to 3.9%.
• Can result from strabismus, form deprivation (e.g., due to congenital cataracts or corneal opacities), and various types of refractive error. These errors include anisometropia (unequal refractive error between the 2 eyes), isoametropia (high but similar refractive error in the 2 eyes), and high astigmatism in 1 or both eyes.
• Amblyopia due to strabismus with or without refractive error is commonly treated with initial optical correction, and subsequent patching or atropine penalisation of the better-seeing eye. Amblyopia due to refractive error alone frequently responds to optical correction alone.
• Amblyopia due to form deprivation is treated initially with early surgery, to remove the visual obstruction. In unilateral or asymmetric cases, patching of the better-seeing eye is necessary after surgery.
• Treatment is highly successful when instituted during infancy and pre-school years, although some children as old as 13 to 17 years respond to treatment, particularly if there has been no prior therapy.