The majority of preschool children in the United States are not screened for visual problems. To avoid permanent visual loss, standardized screening should be incorporated into well-child examinations so that treatment can be initiated promptly. Newborns should be checked for the red reflex, pupillary responses and any constant eye deviation. Infants six months old should be checked for these responses and for "fixation and following" and ocular alignment. Visual acuity should be tested in three- to four-year-old children using the "tumbling E" test, Allen pictures or the HOTV chart.