| All commonly used tests of color deficiency measure color discrimination; plate tests (e.g. Hardy Rand Rittler (HRR)), anomaloscope (e.g. Nagel), arrangement tests (e.g. Farnsworth D-15). Because none of these clinical tests directly measures color detection sensitivity, which can be an important aspect of color vision in certain situations, we have developed and tested an approach to accurately measure color detection sensitivity. We concentrated upon anomalous trichromats because this color vision deficiency is most common (6% of males) and because its manifestations are notoriously heterogeneous.; The color sensitivity test, which we call the Red Test, is a large, stationary, increment of long wavelength light presented upon a bright white background which is a collection of features known to favor color system detection. We compared detection thresholds in the Red Test to several commonly used clinical tests of color discrimination: HRR plate test, Nagel anomaloscope, and Farnsworth D-15 test. None of the commonly used tests predicted performance on the Red Test suggesting that a full evaluation of color vision deficiency requires testing both color discrimination and color detection sensitivity.; Difficulty in finding a consistent color vision test is a current problem, and finding a consistent test which provides an accurate assessment would be beneficial. The current situation is unsatisfactory, both in terms of safety issues, as well as being potentially unfair to suitable applicants. The combination of testing color discrimination and sensitivity will aid in color screening when the ability to quickly and accurately distinguish red lighting is essential (i.e. pilots, railroad workers, and sailors). We recommend the Red Test to provide the necessary pass/fail criteria in conjunction with other tests to safeguard the color screening process avoiding potentially dangerous situations during driving, flying, and piloting a ship or boat. |
