Extremely poor vision can be caused by strabismus in early childhood or by a displaced optical axis. Amblyopia is caused not by organic damage to the eyes but by the brain incorrectly fitting together the images the eyes provide. As a result, the ability to see an object in sharp focus is severely limited. This occurs in more than one in 20 of the German population, as Heike M. Elflein et al. show in a recent original article in Deutsches Ärzteblatt International (Dtsch Arztebl Int 2015; 112(19): 338-44). The authors' study analyzed the visual acuity of over 3200 individuals aged between 35 and 44 years and determined the frequency and causes of amblyopia.
Study participants were examined by ophthalmologists; over 180 participants presented evidence of amblyopia. In half of those affected, lack of visual acuity was caused by differences in refraction between the two eyes (anisometropia); in almost one in four it was caused by strabismus. Because the eyes are actually intact, standard eye examinations do not detect this disease. In everyday life too, the symptoms are almost never detected in children. This has profound consequences, as vision problems caused by amblyopia have to be treated early: the older the child, the lower the chance of successful treatment. The authors therefore indicate that primary care physicians and pediatricians, as well as ophthalmologists, must be vigilant for amblyopia.