We report the results obtained with the Binocular Polaroid Test in a large population screening devised to detect vision disturbances in pre-school age children. The Binocular Polaroid Test is a new test for rapid detection of small unilateral scotoma in the binocular visual field. The test was performed on 1566 children age 3 to 6 years in a field examination. The reliability of the test was controlled in a study examination. A complete study examination was performed in 60 of the 96 subjects with a positive response to the test. One hundred subjects selected at random among those with a negative response were used as controls. The study examination disclosed vision disturbances in 41 of the 60 children with a positive response to the Binocular Polaroid Test. The remaining 19 results were normal. No vision disturbances were detected in the control group. The predictive value and the "phi" coefficient were calculated. The results indicate that the Binocular Polaroid Test appears very suitable for vision screening in pre-school age children for whom an early diagnosis is of paramount importance for treatment and prognosis of a vision alteration.