Increasing use of visual tests in the field of personnel selection,1 special military needs and the rapid expansion of aviation have stimulated interest in technics which measure stereopsis. For several years the Howard-Dolman test of stereopsis2 (not to be confused with the original Howard test3) has been used extensively, and more recently Verhoeff4 has described another method. Verhoeff's test evaluates the acuity of stereopsis by means of a simple device which causes the estimate of relative depth to be based on binocular parallax, eliminates eye-hand coordination and difference in image size as aids in forming judgments and permits little opportunity (1 chance in 65,000) for passing the test by guessing.4 The results obtained when a group of adolescents was given both these tests are discussed in this report.
METHOD
The entire student population of a boys' preparatory school was given a thorough ophthalmic examination,5