[Amblyopia. Epidemiology, causes and risk factors].

BACKGROUND: Amblyopia is the main cause for mostly monocular, impaired vision in childhood. Treatment and prevention of amblyopia is only effective during childhood. Ophthalmological screening of children does not yet exist in Germany. EPIDEMIOLOGY: The prevalence of amblyopia in Germany is 5.6%, which is higher than in reports from studies in Australia; however, the prevalence of amblyopia is not comparable in these studies due to different definitions of amblyopia and the inclusion/exclusion criteria of the study cohorts. At present it is unknown at what age ophthalmological screening should be carried out to prevent amblyopia and the appropriate frequency of screening examinations. CAUSES: Amblyopia is a disorder of the visual cortex that is due to suppression and deprivation of one eye leading to unilateral visual impairment. Approximately 50% of cases of amblyopia are caused by anisometropia, 25% by strabismus and in every sixth person by a combination of both. Other causes, such as unilateral congenital cataracts are relatively rare. RISK FACTORS: A variety of factors, such as ocular pathologies, premature birth, familial disposition and general diseases are associated with an increased risk for amblyopia.