New techniques have permitted serial assessments of visual acuity in infants. Acuity measurements in infants with astigmatism did not reveal meridional amblyopia during the first year of life. Measurements in infants with esotropia showed marked differences in acuity of the two eyes as early as the first 6 months of life. Therapeutic occlusion of the non-deviating eye improves the acuity of the deviating eye but at the expense of the occluded eye. After discontinuing occlusion, rapid increases in acuity of the formerly occluded eye can occur.