Page 70 - Journal of Special Operations Medicine - Winter 2016

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

Michelle Pedler, BSc (Hons); Frank Ruiz, BA; Micaela Lamari;
Charles Hutchinson, DO; Brandon Noyes, DO; J. Mark Petrash, PhD;
Chris Calvano, MD; Anthony La Porta, MD; Robert W. Enzenauer, MD

ABSTRACT
Background: Success in Special Operations Forces med- ambient/daytime illumination to low-level/night light,
icine (SOFMED) depends on maximizing visual capa- the visual system needs time to adapt to the new dark
bility without compromising the provider or casualty conditions (i.e., dark adaption).
when under fire. There is no single light that has been
deemed “ideal” for all SOFMED environments. Meth- In this study, we evaluated red-green and blue tactical
ods: We used the Farnsworth-Munsell (FM) hue test to lighting compared to white light to determine the qual-
determine color vision of normal subjects under white, ity of illumination specifically for TCCC. The study
red-green, and blue flashlights to determine color dis- hypothesis was that red-green light would provide bet-
crimination. Then we used a timed color-determination ter color discrimination than blue light-emitting diode
visual test to determine how quickly normal subjects (LED) illumination and possibly would reduce dark
can identify color correctly. We had subjects perform a adaption time.
simulated surgery illuminated by a normal white-light
source, then by red-green or blue light-emitting diode Materials and Methods
(LED) tactical light. Results: The total error score for
white light was 49.714, 272.923 for red/green light, Fourteen normal-vision volunteers (8 men and 6 women),
and 531.4 for blue light. The subjective perception of ages 18–65 years, gave informed consent before partici-
simulated trauma wounds was not substantially differ- pating in a color-vision study that was approved by the
ent with red-green LED tactical light when compared Colorado Multi-Institutional Review Board (clincaltrials
with white LED light. However, simulated surgery un- .gov listing NCT01927536, https://clinicaltrials.gov/ct2
der the blue LED was more difficult compared with /results?term=NCT01927536&pg=1). Each subject per-
simulated surgery under the red-green LED light. formed a quantitative and qualitative color- vision test,
Conclusion: Red-green was a superior light source for using the FM test under white flashlight conditions
SOFMED and military first responders in this study, es- (Tomahawk NV; First-Light USA, https://www.firstlight
pecially, where light was required to allow accurate and -usa.com) and two tactical illuminations provided by
efficient application of Tactical Combat Casualty Care the red-green LED flashlight (Red-Green Tomahawk
to injured personnel. MC; First-Light USA; Figure 1) compared with another
popular, tactical blue LED flashlight (Blue Tomahawk
Keywords: night vision; tactical combat casualty care; NV; First-Light USA).
TCCC; LED flashlight; Special Operations Forces medicine;
SOFMED The FM test is a qualitative and quantitative evaluation
of color vision consisting of 85 colored papers mounted
in plastic caps. The 85 different color caps are selected
to represent equal steps in color difference around a
Introduction
complete color circle. The caps are divided into four
Military first responders require enough light to allow groups, with each group assigned to a separate test tray
accurate and efficient application of Tactical Combat representing a quadrant of the color circle. The test sub-
Casualty Care (TCCC) to injured personnel. First, there ject was given appropriate time to sort 85 color circles
is the issue of balancing the benefits of providing the in order of perceived differences along a color gradi-
luminance required for task completion against the risk ent. The test administrator then determined the total
for tactical compromise associated with higher illumina- number of errors and their position on the color circle.
tion. Second, when an individual quickly transits from Scores deviating from normal were taken as a diagnosis

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