SCREENING FOR SUPPRESSION IN YOUNG-CHILDREN - THE POLAROID SUPPRESSION TEST

Background: Assessment of monocular visual impairment during screening of young children is often hampered by lack of cooperation. Because s trabismus, amblyopia, or anisometropia may lead to monocular suppressi on during binocular viewing conditions, a test was developed to screen far suppression in young children. Methods: Children were invited to look through two polaroid filters of different polarization direction at two pictures covered with polaroid filters of opposite polarization direction. In this way, each eye could only see one of the two pictur es. in cases of suppression, only one picture would be visible. Acuity measurements in 201 B-year-old children were compared with the Polaro id Suppression test (PST) results. Results: The PST had a high success rate (99.5%) and testing time was under 1 minute. Specificity of the PST for acuity impairments was 91%. The low sensitivity of 60% was cau sed mainly by the fact that some children with binocular acuity impair ments were not detected with the PST. However, the PST was highly sens itive for significant interocular acuity differences. Conclusion: The PST has been found to be a useful screening method for amblyogenic fac tors in young children. The test can be carried out without occlusion of one eye. The apparatus is portable, the test duration is short, and the costs are low. The results indicate that the PST is a very promis ing tool to use in clinical conditions and for screening large numbers of young children.