Carley Swetz, Dr. Tod W. Burke, and Dr. Stephen S. Owen
Individuals with color blindness can benefit law enforcement and other first response agencies in a number of different ways.
Consider the following hypothetical scenario: An armored truck is robbed at gunpoint by a group of individuals who made their escape in a privately owned vehicle. The two uniformed officers are injured and unable to pursue the perpetrators who also elude local law enforcement. Footage of the robbery and parts of the chase scene are captured on surveillance cameras which show the suspects making a foot escape into a heavily wooded area.
Investigators put together a team of highly trained individuals to locate the perpetrators. Due to the unique visual capabilities associated with color blindness, color-blind members of the search team are able to locate the perpetrators in the woods more quickly than persons with normal color vision.
The purpose of this article is to identify the ways in which color-blind individuals may aid law enforcement agencies in some of their field operations. The article will provide an overview of color vision, the differences in vision between color blindness and normal vision, and why persons with color blindness may be an asset to law enforcement (and other first responders).
Overview of Color Vision Perception
Color vision perception is a complex process. Lieutenant Michal Kinney, a US Navy Aerospace Optometrist with the Navy Aerospace Medicine Institute and Research Center, shared information about color vision. According to Lt. Kinney, the ability to visualize colors comes from the reflection of light within the retina of the eye. Differences between colors are based on the color perception, often known as the color spectrum, within the retina.
The retina is comprised of two types of cells, known as cones and rods, which are sensitive to wavelengths of light. When activated by particular wavelengths, these cones and rods produce photo pigments of different colors in the retina. In turn, it is these photo pigments, also known as photoreceptors, which produce chemical changes which allow individuals to perceive color. Individuals with a normal color perception possess the ability to access all cones pertaining to color on the spectrum; individuals without full use of a cone are unable to view certain colors on their color spectrum.
Overview of Color Blindness
Normal color perception, also known as trichromatic vision, occurs when long, middle and short wavelength cones are all present and functional. Long or L-cones produce a red color; middle or M-cones produce a green color; and short or S-cones produce a blue color. The absence of a cone can render individuals unable to fully process color associated with the missing cone.
Color blindness is widely known as the inability for individuals to distinguish between different colors on the color spectrum. Worldwide, 2.4% of individuals are born with some degree of color blindness. Causes of color blindness may include genetics or a disruption between the neural pathways of the eye and the brain.
There are numerous classifications of color blindness based on which cones are affected and how they are affected.
- Anomalous Trichromats access all three cones, but with a slight abnormality in one cone. Depending on which cone, the range of color vision may change. Individuals may have normal color vision or may experience a “faulty” color pertaining to the cone which is involved.
- Dichromats access only two of the three types of cones and have the total absence of function or limited function for colors pertaining to the inaccessible cone. However, certain cones may overlap, such as red (L-cones) with green (M-cones), causing deficiencies within both. This overlap is what leads to the condition most commonly known as red/green color blindness.
Further classification is based on the specific cones involved and the color perceptions associated with them:
- Deuteranomaly, the most common form of color blindness, lacks identification within the M-cones; this results in a distilled green color and difficulty in establishing the green pigments. It may also be challenging to distinguish between red and green.
- Protanomaly lacks identification of the L-cones, making it difficult to visualize red color and the difference between the red and green.
- Deuteranomaly and protanomaly result in difficulties identifying green and red. However, deuteranopia or protanopia are more severe color deficiencies, in which individuals cannot see green (deuteranopia) or red (protanopia) at all.
- An additional form of color blindness, though not the focus of this article, is monochromacy. Individuals with monochromacy do not visualize any colors, instead perceiving various shades of black, grey and white.
Benefits of Color Blindness in Law Enforcement
While color blindness related to protanomaly and deuteranomaly is often listed as a disqualification from becoming a law enforcement officer, it has the potential to benefit law enforcement (and other first responders). For instance, in search and rescue operations, individuals with limited color perception may, in fact, be able to locate items or people which persons with normal color vision would not so readily see.
While individuals with color blindness may not be able to fully identify all colors, other aspects of their vision are heightened. This includes the ability to visualize differences in textures and brightness. In addition, individuals with color blindness may have heightened visual ability for detecting different shades of colors. For instance, a study conducted by Gabriele Jordan, an expert in color vision at the University of New Castle, found that dichromat individuals were able to identify 15 different shades of khaki, while individuals with normal color vision saw no difference between the shades.
Due to the ability to ignore some colors in their environment, dichromat individuals may also more quickly identify differences in patterns and textures, including those located against camouflaged backgrounds. In a 1992 study reported through the Royal Society of London for the Biological Sciences, scientists tested the capabilities of individuals with color blindness to detect camouflaged objects which were not detectable by individuals with normal color vision (trichromats). The study found that individuals with color blindness could distinguish texture, size and orientation from the background elements, allowing them to diffuse the camouflage capabilities. Specifically, dichromatic individuals identified the target region within the camouflage more quickly than trichromatic individuals. This suggests that dichromats can better distinguish color from texture, making them less vulnerable to camouflaged backgrounds.
The previously mentioned attributes may assist in law enforcement duties, such as search and rescue operations, finding missing persons, or locating evidence, due to heightened abilities to distinguish shades, textures, and backgrounds. These unique visual capabilities are directly related to vision perception stemming from color blindness; however, many law enforcement agencies reject applicants who are color-blind.
Hiring officials argue that normal color vision is a legitimate job qualification. Color vision may be measured by job-related tasks an individual must perform. Agencies may use different methods in testing for color blindness, but most share three common components: visual acuity, which is an individual’s visual attention to detail; peripheral vision, which is the ability to see and identify an object regardless of movement and contrast; and visual color.
Multiple tests can serve as diagnostic tools, but do not generally test for job tasks, such as search and rescue, locating missing persons, and identifying evidence; as such, specific additional testing and training in these tasks may be necessary before deploying color-blind individuals to these areas.
Potential Concerns in Hiring Individuals with Color Blindness
Although individuals with color blindness can assist law enforcement (and other first response) organizations with many tasks, agencies may have concerns about hiring color-blind individuals. It is important for agencies to determine and document what levels of color perception are necessary for required occupational tasks – most notably, to protect the safety of officers and of the communities they serve – and to provide proper testing for that.
At the same time, agencies differ on policies related to hiring individuals with color blindness. Some agencies consider color blindness to be an automatic disqualifier. Other agencies are less stringent, allowing individuals with color blindness to be hired so long as they meet certain minimum thresholds for vision. As suggested by these differences, agencies must make their own determinations on the benefits of hiring color-blind individuals. Findings, such as those presented above about the enhanced visual perceptions associated with color blindness, can inform discussions and decisions in this area.
Individuals with color blindness can provide unique and advantageous abilities to law enforcement and other first response agencies by assisting in tasks related to missing persons, evidence recovery, and search and rescue operations. Including at least one person with unique color perception during such operations may have the potential to enhance operational effectiveness.
For agencies which allow hiring of persons with color vision deficiencies, there may be persons on staff whose visual abilities can be utilized. In addition, reserve corps, volunteer based search and rescue organizations, and interagency partnerships can allow persons who, though not serving as sworn officers, may be of assistance in selection missions (presuming that they have the training to do so and that the area has been cleared for nontactical personnel to enter).
Individuals with color blindness can benefit law enforcement and other first response agencies in several ways, including identification of evidence, assistance in search and rescue operations, and assistance in finding missing persons – all of which are critical and often time-sensitive activities. Color-blind individuals should not be viewed by law enforcement as having a deficiency, but rather, research, as noted above, suggests that color blindness may provide benefits to law enforcement and other first responders, aiding with a variety of public safety operations.
Ms. Swetz is a Training Specialist for FEMA. Ms. Swetz can be reached at firstname.lastname@example.org
Dr. Burke, a former Maryland police officer, is a retired professor of criminal justice. Dr. Burke can be reached at email@example.com
Dr. Owen is a professor of criminal justice at Radford University, Radford, Virginia. Dr. Owen can be reached at firstname.lastname@example.org