Red-Green Versus Blue Tactical Light: A Direct, Objective Comparison.

ABSTRACT

BACKGROUND: Success in Special Operations Forces medicine (SOFMED) depends on maximizing visual capability without compromising the provider or casualty when under fire. There is no single light that has been deemed "ideal" for all SOFMED environments. METHODS: We used the Farnsworth-Munsell (FM) hue test to determine color vision of normal subjects under white, red-green, and blue flashlights to determine color discrimination. Then we used a timed color-determination visual test to determine how quickly normal subjects can identify color correctly. We had subjects perform a simulated surgery illuminated by a normal white-light source, then by red-green or blue light-emitting diode (LED) tactical light. RESULTS: The total error score for white light was 49.714, 272.923 for red/green light, and 531.4 for blue light. The subjective perception of simulated trauma wounds was not substantially different with red-green LED tactical light when compared with white LED light. However, simulated surgery under the blue LED was more difficult compared with simulated surgery under the red-green LED light. CONCLUSION: Red-green was a superior light source for SOFMED and military first responders in this study, especially, where light was required to allow accurate and efficient application of Tactical Combat Casualty Care to injured personnel.