I teach low-light classes nationwide and last year I noticed a dramatic increase in students who arrived for my classes equipped with strobe-capable lights.
As to the exact reason for this phenomenon, I can't tell you for sure. It could be the result of the manufacturers' aggressive advertising, a more economical price point on lights that have this feature, or the fact that strobe-capable lights have risen to the top of the latest "have to have" gear on many officers' lists.
The one thing I can tell you is that many of the students who arrive for my classes with their strobing lights ready to go are often not aware of the pros and cons of strobe light deployment. Many, in fact, believe that the disorientating effect of a strobe light exposure is a relatively new innovation.
The Bucha Effect
Let's look at the history of disorientation caused by strobe light exposure. The phenomenon that occurs when a person experiences dizziness and confusion when exposed to strobe lighting was first identified by a Dr. Bucha in the 1950s when he was asked to investigate a series of unexplained helicopter crashes.
After the crashes, surviving crew members said they experienced dizziness and disorientation from the strobing effect of rotating helicopter blades. The crews reported looking up at the sky with the rotors spinning above, creating the strobing effect that caused the disorientation. The rotor blades of the helicopter caused the sunlight to strobe in the eyes of the pilots, causing them to lose control of their machines. Dr. Bucha's first name has been lost to history, but this phenomenon has been known as the Bucha effect ever since.
Benefits of Strobing Lights
Fast forward to the recent spike in popularity of the tactical strobe light we see today. The human response to strobe light exposure is not new but the creation of the strobing flashlight and the method and instrument of delivery continues to evolve.
Is the strobe light a gimmick or a viable tactical innovation? Do the positive benefits of strobe light deployment outweigh the negatives?
Here are some of the claims that are made in regard to the effects of a strobe light exposure.
- Disorients the suspect
- Diminishes an assailant's night adaptation
- Causes a disruption to the subject's vision, which affects his or her ability to use force
- Provides a visual and psychological hurdle to aggression
- Decreases the suspect's direct and peripheral vision
- Induces fear
Let's take a more in-depth look at some of these claims.
Flash/strobe disorientation is the result of an "after image" or temporary visual imprint caused by a brief exposure to high-intensity light levels. This image varies with light level and time duration or frequency of the exposure. The disorientation occurs as specific light frequencies affect the brain and the light cycles through those frequencies too fast for the brain to adjust.
Strobing tactical lights do not allow the photoreceptors to reset, which shocks an individual's vision. Strobing bright light forces the brain's perception input to arrive in segments, thus creating after images as the brain labors to fill in or complete the partial image created by the momentary exposure of the strobe. These after images compound with each strobe exposure, which increases perceptual disparity.
Police tacticians have long recognized the blinding caused by placing the hotspot of a high-intensity light in a subject's eyes. Add the disorientation caused by the strobing of a quality bright light and the benefits are obvious. However, these benefits also come with some disadvantages and tactical concerns.
When deployed without the benefits of an accompanying constant light (cover officer), a strobe light may make the user experience an inability to see or recognize subtle/deliberate slow movements made by the suspect.
In training classes I am routinely able to move my hands eight to 10 inches before my threatening motions are recognized by the student who is exposing me to the strobe. Of course, my movements must be very slow and deliberate in order to avoid detection by the student.
Also, exposure to any bright light in a dark environment after low-light adaptation has been achieved will in fact deteriorate a subject's night vision. However, I have not been able to verify the claim that strobe exposure will diminish night vision adaptation to any greater degree. Much in the way that a brief exposure of a bright light in a person's eyes from a flash into a mirror while clearing a bathroom will cause some discomfort and a momentary disoriented state, we do not lose our established night vision to any significant degree. In multiple tests with students on the live fire range, I have not seen any significant loss of target identification or engagement after the strobe exposure has been ended and the eyes are given just seconds to adapt.
As to the claim that strobe exposure causes a disruption to vision that affects the suspect's ability to use force, I agree.
This is obvious to anyone who has ever applied the strobe exposure to another person. It is often stated that humans are 70 percent to 80 percent visual. This is true. And it is very difficult to formulate any type of plan, coordinate physical movement, or manifest any effective aggression without an intelligent assessment to build on. This is impossible to do while experiencing a strobe exposure.
During a lethal confrontation, lack of information/intelligence can be stress inducing in itself. Much in the same manner as stated above a strobe exposure will provide a visual and psychological hurdle to aggressive movement or behavior. It is the fear of the unknown in many cases. During a strobe exposure, a suspect is unable to identify the officer by size, number, physical presence, exact location, environmental conditions, and much more. Without many of these points of intelligence, the suspect is incapable of developing a plan with any expectation of success.
That strobe exposure decreases the suspect's direct and peripheral vision is another claim we must look at realistically. Without question, direct and peripheral vision are decreased.
However, is there a significant increase in this vision deterioration as a result of the strobe exposure over just a constant bright light? If the suspect and the officer remain stationary, I say there is not a significant increase as a result of applying the strobe. Exposure to a quality bright constant light will significantly decrease the suspect's direct and peripheral vision. In student testing, I have not seen any measurable difference between applying the strobe and a bright constant light.
While performing the above-mentioned tests, I did recognize a benefit of the strobe exposure to the officer when the officer moves toward the suspect. In many cases the officer is able to advance or close the gap to the suspect without detection. This same movement is not as successful without the strobe. Using the strobe, the officer is often able to move as much as 25 feet without detection.
Despite popular belief to the contrary, the strobing in itself is not a fear inducer. It is the disorientation and confusion caused by the strobe exposure that leads to fear in some people. In most cases when you can limit the suspect's ability to gather and process intelligence you can increase the potential for fear. The strobe exposure certainly provides this limiting factor and can be particularly effective due to the accompanying disorientation experienced.