Amblyopia is the leading developmental and non-pathological cause of visual impairment in children, affecting 1–3.6% of the population (Williams et al. 2008). The disorder causes a range of monocular visual defi cits, including reduced acuity, a loss of contrast sensitivity and visual distortions. Most cases are unilateral and are the result of strabismus, anisometropia, or a combination of both. A less frequent cause is an obstacle to form vision, such as congenital cataract or large symmetric refractive errors, when the amblyopia may be either monocular or binocular (Wallace et al. 2007)