To evaluate the modified Teller visual acuity test as a mass screening tool for testing visual acuity in infants and preverbal children. Prospective case series. A total of 1126 healthy children undergoing mandatory examination at the Mother and Child Health Center. Visual acuity was tested by the modified Teller visual acuity test. Visual acuity was measured in all children. Clinical evaluation was performed in children who failed the Teller acuity test and in a control group. Visual acuity was below the normal range in 5% of the children. In the study group referred for complete eye examination, there were 9% false-negative and 44% false-positive results. In the age range of 12 to 17 months, false-negative and false-positive results were obtained in 5.6% and 50% of the children, respectively. The Teller acuity card procedure can be used for vision screening in preverbal children. Testing was associated with a high rate of false-positive results.