THE PERFORMANCE OF THE FARNSWORTH LANTERN AT THE SUBMARINE MEDICAL RESEARCH LABORATORY AND IN THE FIELD FROM 1955 TO 1965

Abstract : The Farnsworth Lantern is a color vision test which presents specially selected pairs of red, green, and white lights. It was developed for Naval use by the late CDR Dean Farnsworth, MSC, USNR, when he was attached to the Submarine Medical Research Laboratory. Whereas the set of pseudo- isochromatic plates which is the other color vision test commonly used by the Navy was designed to pass normals and fail all color defectives, the Farnsworth Lantern was designed to pass normals and the mild color defectives and to fail the moderate, severe, and dichromatic color defectives. Good color vision is required for acceptance to many Naval training schools because, upon completion of the training, the man will be called upon to make critical color judgments as part of his Naval duties. When plates were used as the qualifying color vision test for acceptance to these schools, all color defectives - ten per cent of the applicants - were rejected (when the plates were correctly administered). With the introduction of the FaLant as a qualifying test, thirty per cent of the color defective population is being salvaged, (that is the FaLant passes three of the ten men in a hundred who are color defective) by rating them as safe for making accurate color judgments. This Farnsworth Lantern has been in use at the Submarine Medical Research Laboratory and at various Naval activities, such as hospitals, training schools, air stations, et cetera, for some ten years. The paper analyzes its performance here at SMRL and in the field during this period (1955 - 1965).