■Vision screening for children may be considered in terms of detection of amblyopia, strabismus, and/or refractive error. Variations exist within and between countries regarding vision screening for children in terms of program content, referral criteria, and personnel. Recommendations state pre-school vision screening programs be conducted by orthoptists or by professionals trained and supported by orthoptists.

■The justifications of vision screening for children include an increased risk of blindness to the healthy eye as a result of injury or disease in adults with amblyopia. An increased risk of blindness is present as the non-amblyopic eye of an amblyope may become diseased or injured.

■A recent report found that screening for amblyopia could not be considered as cost-e ective, but acknowledged that much uncertainty exists surrounding the shortand long-term implications of the condition(s). Further research is needed to provide such evidence.

■Treatment of amblyopia associated with refractive error should incorporate a period of observation with glasses-wear alone to allow for “refractive adaptation” (also known as “optical treatment of amblyopia”). Improvements in visual acuity (VA) can occur up to and beyond 20 weeks after glasses are prescribed. Most improvement

occurs in weeks 4–12. In some cases, further amblyopia therapy may not be required.

■Children who undergo amblyopia therapy at an early age have been found to respond more quickly to occlusion than older children, and require less occlusion in total. There is evidence to suggest that successful treatment of children aged over 7 years can be achieved in cases of anisometropic, strabismic, and mixed etiology amblyopia.

■Atropine has been found to be as e ective as patching in the treatment of both moderate and severe amblyopia.

■Recurrence of amblyopia may occur following treatment, with reported rates of 7–27%. Factors influencing recurrence include age of the child at cessation of treatment,VA at the time of cessation of treatment, and the type of amblyopia that is present.

■Reported health-related quality of life (HRQoL) implications of amblyopia include the impact of the condition upon stereoacuity; fine motor skills; reading speed; and interpersonal relationships.

■The reported HRQoL implications of strabismus are related to physical appearance, particularly upon self-image and interpersonal relationships. Surgical correction of strabismus has been reported to improve HRQoL.

8.1 Amblyopia

Amblyopia is a sensory anomaly defined as defective unilateral or bilateral visual acuity (VA). There are a number of classifications of amblyopia based on the etiological cause(s). The reported prevalence of amblyopia varies widely, from 1–5%. Di erences in prevalence can be attributed to the population studied (e.g. ethnicity), and

whether the study sample was taken from a clinical cohort (where a greater prevalence would be expected), or a pop- ulation-based study. However, the most important factor that can account for the di erences in the reported prevalence rates is that of amblyopia definition. Over the recent years, a definition of amblyopia based upon a di erence in VA of two or more Snellen or logMAR lines between eyes has been adopted. However, there is no universally