FREE e-Newsletter
Important News - Hot Topics
Get them Now!

The Law Officer's Pocket Manual - Bloomberg BNA
This handy 4" x 6" spiral-bound manual offers examples showing how rules are...


How to Use a Strobing Flashlight

Strobes have become extremely popular on police flashlights, but this tool has its pluses and minuses.

June 30, 2010  |  by Edward M. Santos

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.

It isn't.

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.

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. 

Request more info about this product / service / company

Comments (15)

Displaying 1 - 15 of 15

Neil Murphy @ 2/2/2012 12:40 PM

I am curious. On TV cops (a generality) use their flashlights overhanded. Is this true? Why?

[email protected] @ 4/17/2012 12:16 AM

so you can crack someons head with the handle another way of protection.

Sias Fourie @ 1/8/2013 12:57 PM

Hi Edward,
To make a long story short, does not allways happen, but I will try and keep it as short as possible. I am an ex Warrant Officer Trainer from the South African Police and I spearheaded the development, the design, together with the current Commander of the Special Task Force in Cape Town, Col Corne Vermeulen. Way back in 2000 and even before that, I started experimenting with the Disorientating effect of the Strobe Light as a Less than lethal tool.
We did not have the very bright LEDS we have now, but even with a 34 Lumen Krypton Globe 3 D Cell flashlight it worked.
I got involved with Lightsaver and with the help of our sister company, Azoteq we developed a Strobin light running at approximately 7,5 cycles per second, we found was the most disturbing effect we could muster. I did quite a bit of medical research and also used the few prototypes in the SAPS, Crowd Management as well as Crime combating units, operating in the whole of the Cape Peninsula. I wrote down a few of the bright points (excuse the pun) and put together a lecture to be added on to Low light training. Lou Chiodo from the States as well as Don Gold took an interest and the thing got of the ground in the SAPS. I left the SAPS in 2003 and joined Lightsaver as a sales Manager as well as their Technical advisor to supplying equipment to the SAPS and other Law enforcement agencies. I undertook a coutrywide tour and visited som Tactical Response teams and introduced them to the Disoreintation Strobe in a Low light workshop.
I want to stop here with what we have tried to do, but I need to say a few things about the Light and how people (trainers and users in the field) approaches it. It is done with suspicion and rightly so, because I really believe that if it was easier to accept by Law enforcement, it would have also been accepted by the criminal.
Please keep in mind that this is a major find in the hands of police officers who only wish they can lay their hands on.
Contact me - Sias.

K. vd Linden @ 3/3/2013 7:13 AM

Hi Edward,

I am an "oldtimer" at the police force in Amsterdam, started in January 1972.
Last 11 years I am a police trainer at the Dutch Police Academy. Before that I was working in special squads and some special units since 1977 till 2002.
Your findings are 100% correct. Only on 1 part we made a small advancement.
From 2004 on, up till today we are developing the use of Strobe lights for our tactical training (95% hand to hand and 5% weapon training). After 3 years training/development/pilots in practice with 400 students, we came to the point that we needed a light that no manufactor produced (or wanted to). So we designed a tactical light that covered our needs. To use a light tactical is not only the light, but a complete package. It starts with 1-handed quick draw, upside down with momentary switch on the rear, thumb operated, always on in Strobe, (under stress you don't have fine motorical skills)
It is attached with a small spiral cord to your holder so You can drop your light during the arrest.
It is usable as a normal light, but then you have no stress and can hold the switch 2 sec for high, med, low modes.
After switch off. . . .it always starts up in tactical Strobe.

To counter the effect You described that you can move your hands several inches before detection, we set the strobe to 20hz.
After many tests we found that it was still very difficult for the suspect to locate the position and distance to the operator, and there was no chance anymore to move your hands without detection.
So this was the con. are brought down to a minimum and the pros are still in function.
contact me for more info or photo's of the light we have developed.

friendly regards
K. van der Linden

Dale D. @ 9/3/2013 5:25 AM

Edward, I read your forum and I wanted to let you know that I am an inventor that recently developed

CJ Rigdon @ 12/27/2013 12:04 PM

Wow, I never knew that the idea of using a strobe light to disorient attackers went so far back, though I suppose it makes sense.

In terms of whether the strobe is useful over just a normal bright light, I have to wonder if the advantage of the strobe light comes from destroying night vision. If a light continues to go on and off in someone's face, their eyes will not have time to adjust to either brightness, which can result in them being unable to see. Furthermore, it makes me think of flash on cameras. The more pictures are taken the more "spots" can dance in front of someone's eyes when one is using a flash. The more "spots" there are, the more difficult it is to see. So I would say its entirely possible that a strobe light has benefits that a normal flashlight might not.

The best option might be to have a tactical flashlight that can work as both a strobe light and a normal light, such as the versatile LazerBrite:

In any case, great article!

Steven Tope @ 5/12/2014 8:38 PM

Hello. I would be interested in learning more about the light that Mr. K van der
Linden wrote about, i.e., any specific information regarding the size, weight, lumens, price and if it is available for purchase in the U.S., etc. I also would be interested in knowing if there are any other flashlights available in the U.S. which meet the standard that Mr. van der Linden wrote about in his 3/3/2013 post. Thank you.

Charles Ramsey @ 5/21/2014 5:52 PM

Actually these lights are causing epileptic seizures and deaths in those with photic or pattern epilepsy. I believe these lights kill more innocent people than all other police caused deaths combined. There is no reason to use these on people who are not breakng the law. Stay tuned there will be lawsuits against the police and the nanufacturers.

June @ 6/10/2015 5:57 AM

I'm in agreement with Charles Ramsey and I thank him for mentioning this. I ended up reading this article because I was trying to research the use of flashing lights in TV shows. Even that much is extremely painful to me and often triggers an epileptic attack. My epilepsy is genetic, it came from my father and probably others in my family, there is no control for it except medications and a special diet. I didn't know police were using such lights. If it were used on me and triggered an attack, I would be rendered completely catatonic and possibly speechless only able to make moaning sounds. Even though I can hear and understand the person, I cannot speak. It would also cause such pain that I can't move and would likely collapse into a fetal position. Police should be aware of the non-violent reaction that this may produce in some people. Unfortunately, without special training in this, it's very dangerous and negative results are certain with some cases. Please be careful.

Mike Van volkenburg @ 7/27/2015 4:46 PM

7 sycles per second is the median frequency of the alpha waves of the brain. External inputs of energy aka strobes, can cause epileptic seizure, unconciousnes and a number of related problems. This has been common medical knowledge for decades and is used by licensed physicians in some treaatments.

Hrrrng @ 9/24/2015 11:12 PM

Also accidentally sending epileptic suspects into potentially life threatening fits is a problem

Chuck @ 10/9/2015 10:09 PM

Left out one of the easiest and best uses--a strobe makes movements much more visible, making it very difficult to hide.

Most strobe flashlights don't hit the optimum frequencies for disorientation (Fenix w/ their 7.8Hz is the only one I know of,) but even the cheapest flash, held steady will cause any movement in field to be very visible.

Ideally, you need a visor which will sync with the flash so that YOU aren't disoriented...while this wouldn't be difficult, I'm not aware of any such units for sale. (A flash at the proper frequency in blue light, viewed through a green filter (with a green steady light) would provide near perfect vision for the operator while still disorienting the subject. As an alternative to synchronizing a visor with the light.)

Given the difficulty the American police have in properly training officers to bring in suspects alive and unharmed--something most European forces have no problem doing, such non-lethal tools need to be exploited.

Jack @ 5/7/2016 10:43 PM

We must also consider the fact that a pulsed power LED consumes much less battery power than a light of the same power being on all the time. This fact allows for much smaller units using smaller available batteries.

Zvi Harduf, Ph.D. @ 5/16/2017 2:54 AM

I failed to locate the time-pattern of the effect: is it immediately induced, are there significant individual variations between genders, ages etc.

Zvi Harduf, Ph.D. @ 5/24/2017 2:33 AM

Dear Dr Santos.
I failed to locate the time-pattern of the effect: is it immediately induced, are there significant individual variations between genders, ages etc.
Are these DATA available?

Join the Discussion

POLICE Magazine does not tolerate comments that include profanity, personal attacks or antisocial behavior (such as "spamming" or "trolling"). This and other inappropriate content or material will be removed. We reserve the right to block any user who violates this, including removing all content posted by that user.

Other Recent Stories

Hurricane Response: Weathering the Storm
By the time Florence blew into Wilmington, a city of around 100,000 people, she was much...
Police Supporters
This holiday season you should know that most Americans support you and respect you.
Flying Cross: External Carrier Compatible Outerwear
How do you create outerwear that protects officers from the elements in all types of...

Police Magazine