laser pointer visibility with lcd monitors free sample

This page presents laser safety equations and example calculations. These are valid for the type of lasers commonly misused by the general public: laser pointers and commercially available handheld lasers. Specifically, this means lasers emitting visible light (400-700 nanometers) that is continuous (e.g., not pulsed lasers).

Also, these equations assume an unwanted exposure where a person would move and/or close their eyes within 1/4 second of seeing the bright light. This is a standard assumption in the laser safety field. The Maximum Permissible Exposure value for a 1/4 second exposure is therefore applicable. (Injuries have occurred where a person deliberately stared into a laser beam for much longer than 1/4 second. See this list of self-inflicted laser eye injuries for some examples.)

It is easy to calculate the eye hazard distance (NOHD), and the three visual interference distances corresponding to flashblindness, glare and distraction. All you need to know is the laser’s power in milliwatts, the beam divergence in milliradians, and the beam color (from which we determine theVisual Correction Factor).

If you don’t know the beam divergence, use 1 milliradian for lasers under 500 milliwatts in power, and 1.5 milliradians for lasers 500 milliwatts and above. Here are the equations, which are explained in much more detail below.

These calculationsmake some simplifying assumptions which are valid for continuous-wave visible lasers at aircraft distances. The SZED differs from the formula found in FAA Advisory Circular 70-1 by converting watts to milliwatts. This in turn makes the constant under the square root to be “12.7” and not the “1.27” found in AC 70-1

For pilots, an important concept is the Nominal Ocular Hazard Distance. Laser safety experts recommend not having direct eye exposure to a laser’s beam closer than the NOHD for that laser. That’s because the beam’s power density (irradiance) from the laser source to the NOHD exceeds the Maximum Permissible Exposure limit set by scientists of 2.54 milliwatts per square centimeter. Once beyond the NOHD, the beam is considered completely eye safe since the irradiance falls below the MPE limit.

However,this does not mean that an eye exposure within the NOHD willautomaticallycause an eye injury, or even is likely to cause an injury.The NOHD is a “nominal” hazard distance, not an actual hazard distance.

[Technical details: The ANSI Z136.1 laser safety standard sets the Maximum Permissible Exposure to be “a factor of 10 below the 50% damage level.” Exposure at the MPE gives “…a negligible probability of damage.” For visible light (and near infrared light) “the MPE is well below the exposure required to produce a minimal (or threshold) lesion. For purposes of this standard, a minimal retinal lesion is the smallest ophthalmoscopically visible change in the retina. This change is a small white patch (apparently coagulation that occurs within 24 hours of the time of exposure.)]The location along a beam path where the exposure is 10 times the MPE is at 31.6% of the NOHD. This means that at a distance of 31.6% of the NOHD, there is a 50/50 chance that an exposure will cause a minimally detectable change to the retina. We call this the ED50 (Exposure Dose 50%) distance. The diagram below color-codes a laser’s eye hazard, so red is a definite hazard, yellow is a potential hazard, and green is not considered to be hazardous.

Click on the chart to see it larger.For all lasers of this type, the ED50 distance (marked “50/50” on the chart) is 31.6% of the Nominal Ocular Hazard Distance. As you can see from the yellow-green and green areas, the NOHD concept includes a built-in “safety margin.”

The FAA is not only concerned with pilots’ eye safety. They also are concerned with safe but too-bright lasers. Effects such as temporary flashblindness, glare and distraction can interfere with pilots’ vision and performance.

Critical Zone Exposure Distance: The beam is bright enough to cause a distraction interfering with critical task performance, from the source to this distance. Beyond this distance, the beam is 5 μW/cm^2 or less (below 5 microwatts per square centimeter).

“Laser-Free” Exposure Distance: Beyond this distance, the beam is dim enough that it is not expected to cause a distraction. This light level is 50 nW/cm^2 or less (below 50 nanowatts or 0.5 microwatts per square centimeter).

This bar chart shows the NOHD (black) and visual interference distances (red, orange and yellow) for two 800 mW, 1.5 mrad lasers. They both have the same NOHD since the output power is the same. However, one laser emits green light. The human eye is more sensitive to green, so it is a visual hazard at a greater distance than an equivalent blue laser.

For the blue laser, the flashblindness hazard (385 ft) is shorter than the NOHD (437 ft). This is due to the deep blue light not being sensed well by the eye’s retina. All of the laser power is going onto the retina -- that’s why both the green and blue lasers have the same NOHD of 437 ft. But the blue light is not seen well, so it can only flashblind up to 385 ft. In this case, the NOHD is more important. A person getting the direct beam in their eye should be farther than 437 ft, if possible.

To calculate the NOHD, you need to know the laser’s power in milliwatts (mW) and the beam divergence in milliradians (mrad). For NOHD calculations, the wavelength (color) does not matter.

If you know the power in watts, multiply by 1000 to get the power in milliwatts. For example, a 1 watt laser is the same as 1000 mW; a 1.5 watt laser is the same as 1500 mW.

The NOHD equation below is derived from FAA’s Advisory Circular 70-1, which in turn derived it from an equation in the ANSI Z136.1 laser safety standard. The ANSI equation was re-expressed by the FAA in a simpler form and to put the answer in feet. The equation makes some simplifying assumptions which are valid for continuous-wave visible lasers at aircraft distances. Use this equation ONLY for visible continuous-wave lasers (not pulsed lasers).

EXAMPLE 1: In the U.S., lasers sold as pointers must be less than 5 mW. A typical divergence is 1 milliradian. What is the Nominal Ocular Hazard Distance? The 50/50 injury chance distance?

Answer:The Nominal Ocular Hazard Distance of a 5 mW laser pointer with 1 mrad divergence is 51.9 feet. The ED50 distance means that if a person is 16.4 feet from the laser and is exposed under laboratory conditions (the laser and eye are fixed relative to each other), there is a 50/50 chance of causing a minimally detectable retinal lesion.

EXAMPLE 2a:One of the most controversial lasers is the “Spyder III Arctic” made by the company Wicked Lasers. This is sold as a 1 watt laser. The manufacturer says the beam divergence is 1.5 milliradians. What are the NOHD and the ED50 distances?

To calculate the visual interference distances, you need to know the laser’s power in milliwatts, the beam divergence in milliradians, and the color (from which we determine the Visual Correction Factor).

Use the wavelength information below to determine the Visual Correction Factor, or VCF. This is done because the human eye has a different sensitivity to certain colors. We see green light as much brighter than an equivalent amount of red or blue light. The VCF takes this into account. Here are the FAA’s VCF values for the lasers most likely to be encountered by pilots:

Green 532 nm,VCF = 0.8802. The majority of green laser pointers and handhelds currently (2017) sold to consumers. However, 520 nm pointers (VCF = 0.7092) are becoming more affordable and popular. If you do not know which green was used in an incident, assume 532 nm (VCF = 0.8802).

Red 633 nm,VCF = 0.2382. Use this for most red diodes and helium-neon lasers. A 635 nm diode will have a slightly lower VCF (0.2202). If a laser is known to be red, but the exact type or wavelength is not known use a value of 0.2382.

Blue 445 nm,VCF = 0.0305. This is a very popular blue. The original source is diodes taken from Casio “Green Slim” laser projectors. This type of diode is used in the Wicked Lasers Spyder III Arctic and similar blue handhelds.

Green 555 nm,VCF = 1.0. Worst case -- use for ultra-conservative calculations when the wavelength is not known and you want to ensure even the brightest possible color is taken into account.Red 670 nm,VCF = 0.0321. A deeper red used in laser pointers, usually older or cheaper ones

This means that a 5 mW laser pointer could cause temporary flashblindness up to 245 feet, could cause glare up to 1,096 feet, and could be a distraction to a pilot up to a distance of 10,961 feet (2.1 miles).

For all consumer red lasers, if we don’t know the wavelength we use the worst-case common red which is 633 nanometers. This has a Visual Correction Factor of 0.2382.

The green laser is 3.6952 times more visible (compare the VCFs of 0.8802 and 0.2382). However the green laser’s visual interference distances are only 1.922 times longer than the red laser’s (compare the LFED of 10,961.2 feet with 5,702.2 feet). In fact the difference is exactly the square root of 3.6952 (1.922 is the square root of 3.6952).

This shows how if you have two equivalent lasers, except one is a different color, the brighter laser’s visual interference distance will be greater by the square root of the difference in the Visual Correction Factors.

EXAMPLE 3:Compare the NOHD and visual interference distances for a Spyder III Arctic laser. Use the actual output power of 800 mW and the manufacturer’s divergence of 1.5 milliradians.

Recall that the NOHD does NOT depend on the wavelength. However, we do need to know the wavelength to determine the visual interference distances. From Wicked Lasers’ website, we see that the Arctic model emits blue light with a wavelength of 445 nanometers. This has a Visual Correction Factor of 0.0305.

Notice that for this laser, the flashblindness distance of 384.9 feet is actually less than the eye hazard distance (NOHD) of 437.3 feet. This is because the human eye sees blue light poorly -- in this case, only 3% as well as the brightest green light. Although the laser may not appear dazzlingly bright, it still could be an eye hazard to a person within the NOHD. For this reason, you should not allow access within the SZED — the person would still be within the NOHD. You must set the SZED to be the same as the NOHD. (If you were filling out the FAA Advisory Circular 70-1 “Laser Configuration Worksheet,” you would be required to enter “Less than NOHD” in the SZED space.)

Easy Haz software, free online version from Kentek’s Laser Safety U. To use this, you may need to understand scientific notation. Also, results are returned in meters.

Free Laser Hazard Distance safety calculator app for iPhone, iPod Touch and iPad. This app also gives the laser beam’s spot size at the NOHD. The publisher, James Stewart of LVR Limited, has additional low-cost laser safety apps available from the iOS App Store.

Professional programs such as Eazy Haz LSO Edition and Skyzan are available for more complex situations. A search for “laser safety software” can find these programs.

If you are a member of the International Laser Display Association, you can use ILDA’s free online Skyzan professional laser hazard calculator. Here is a sample ILDA Skyzan report for a multi-color (RGB) laser light show taking into account light haze in the atmosphere and restricted beam angles (click screenshot to enlarge):

A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light.

The small width of the beam and low power of typical laser pointers make the beam itself invisible in a clean atmosphere, only showing a point of light when striking an opaque surface. Laser pointers can project a visible beam via scattering from dust particles or water droplets along the beam path. Higher-power and higher-frequency green or blue lasers may produce a beam visible even in clean air because of Rayleigh scattering from air molecules, especially when viewed in moderately-to-dimly lit conditions. The intensity of such scattering increases when these beams are viewed from angles near the beam axis. Such pointers, particularly in the green-light output range, are used as astronomical object pointers for teaching purposes.

Laser pointers make a potent signaling tool, even in daylight, and are able to produce a bright signal for potential search and rescue vehicles using an inexpensive, small and lightweight device of the type that could be routinely carried in an emergency kit.

There are significant safety concerns with the use of laser pointers. Most jurisdictions have restrictions on lasers above 5 mW. If aimed at a person"s eyes, laser pointers can cause temporary visual disturbances or even severe damage to vision. There are reports in the medical literature documenting permanent injury to the macula and the subsequent permanent loss of vision after laser light from a laser pointer was shone at a human"s eyes. In rare cases, a dot of light from a red laser pointer may be thought to be due to a laser gunsight.

The low-cost availability of infrared (IR) diode laser modules of up to 1000 mW (1 watt) output has created a generation of IR-pumped, frequency doubled, green, blue, and violet diode-pumped solid-state laser pointers with visible power up to 300 mW. Because the invisible IR component in the beams of these visible lasers is difficult to filter out, and also because filtering it contributes extra heat which is difficult to dissipate in a small pocket "laser pointer" package, it is often left as a beam component in cheaper high-power pointers. This invisible IR component causes a degree of extra potential hazard in these devices when pointed at nearby objects and people.

Early laser pointers were helium–neon (HeNe) gas lasers and generated laser radiation at 633 nanometers (nm), usually designed to produce a laser beam with an output power under 1 milliwatt (mW). The least expensive laser pointers use a deep-red laser diode near the 650 nm wavelength. Slightly more expensive ones use a red-orange 635 nm diode, more easily visible because of the greater sensitivity of the human eye at 635 nm. Other colors are possible too, with the 532 nm green laser being the most common alternative. Yellow-orange laser pointers, at 593.5 nm, later became available. In September 2005 handheld blue laser pointers at 473 nm became available. In early 2010 "Blu-ray" (actually violet) laser pointers at 405 nm went on sale.

The apparent brightness of a spot from a laser beam depends on the optical power of the laser, the reflectivity of the surface, and the chromatic response of the human eye. For the same optical power, green laser light will seem brighter than other colors, because the human eye is most sensitive at low light levels in the green region of the spectrum (wavelength 520–570 nm). Sensitivity decreases for longer (redder) and shorter (bluer) wavelengths.

The output power of a laser pointer is usually stated in milliwatts (mW). In the U.S., lasers are classified by the American National Standards InstituteFood and Drug Administration (FDA)—see Laser safety#Classification for details. Visible laser pointers (400–700 nm) operating at less than 1 mW power are Class 2 or II, and visible laser pointers operating with 1–5 mW power are Class 3A or IIIa. Class 3B or IIIb lasers generate between 5 and 500 mW; Class 4 or IV lasers generate more than 500 mW. The US FDA Code of Federal Regulations stipulates that "demonstration laser products" such as pointers must comply with applicable requirements for Class I, II, IIIA, IIIB, or IV devices.

Green laser pointersdiode-pumped solid-state frequency-doubled, DPSSFD). They are more complex than standard red laser pointers, because laser diodes are not commonly available in this wavelength range. The green light is generated through a multi-step process, usually beginning with a high-power (typically 100–300 mW) infrared aluminium gallium arsenide (AlGaAs) laser diode operating at 808 nm. The 808 nm light pumps a neodymium doped crystal, usually neodymium-doped yttrium orthovanadate (Nd:YVO4) or neodymium-doped yttrium aluminium garnet (Nd:YAG), or, less commonly, neodymium-doped yttrium lithium fluoride (Nd:YLF)), which lases deeper in the infrared at 1064 nm. This lasing action is due to an electronic transition in the fluorescent neodymium ion, Nd(III), which is present in all of these crystals.

Because even a low-powered green laser is visible at night through Rayleigh scattering from air molecules, this type of pointer is used by astronomers to easily point out stars and constellations. Green laser pointers can come in a variety of different output powers. The 5 mW green laser pointers (classes II and IIIa) are the safest to use, and anything more powerful is usually not necessary for pointing purposes, since the beam is still visible in dark lighting conditions.

Blue laser pointers in specific wavelengths such as 473 nm usually have the same basic construction as DPSS green lasers. In 2006 many factories began production of blue laser modules for mass-storage devices, and these were used in laser pointers too. These were DPSS-type frequency-doubled devices. They most commonly emit a beam at 473 nm, which is produced by frequency doubling of 946 nm laser radiation from a diode-pumped Nd:YAG or Nd:YVO4 crystal (Nd-doped crystals usually produce a principal wavelength of 1064 nm, but with the proper reflective coating mirrors can be also made to lase at other "higher harmonic" non-principal neodymium wavelengths). For high output power, BBO crystals are used as frequency doublers; for lower powers, KTP is used. The Japanese company Nichia controlled 80% of the blue-laser-diode market in 2006.

Some vendors are now selling collimated diode blue laser pointers with measured powers exceeding 1,500 mW. However, since the claimed power of "laser pointer" products also includes the IR power (in DPSS technology only) still present in the beam (for reasons discussed below), comparisons on the basis of strictly visual-blue components from DPSS-type lasers remain problematic, and the information is often not available. Because of the higher neodymium harmonic used, and the lower efficiency of frequency-doubling conversion, the fraction of IR power converted to 473 nm blue laser light in optimally configured DPSS modules is typically 10–13%, about half that typical for green lasers (20–30%).

Lasers emitting a violet light beam at 405 nm may be constructed with GaN (gallium nitride) semiconductors. This is close to ultraviolet, bordering on the very extreme of human vision, and can cause bright blue fluorescence, and thus a blue rather than violet spot, on many white surfaces, including white clothing, white paper, and projection screens, due to the widespread use of optical brighteners in the manufacture of products intended to appear brilliantly white — the brighteners are chemical compounds that absorb light in the violet (and ultraviolet) region of the electromagnetic spectrum and re-emit light in the blue region by fluorescence. On ordinary non-fluorescent materials, and also on fog or dust, the color appears as a shade of deep violet that cannot be reproduced on monitors and print. A GaN laser emits 405 nm directly without a frequency doubler, eliminating the possibility of accidental dangerous infrared emission. These laser diodes are mass-produced for the reading and writing of data in Blu-ray drives (although the light emitted by the diodes is not blue, but distinctly violet). In mid-to-late 2011, 405 nm blue-violet laser diode modules with an optical power of 250 mW, based on GaN violet laser diodes made for Blu-ray disc readers, had reached the market from Chinese sources for prices of about US$60 including delivery.

Laser pointers are often used in educational and business presentations and visual demonstrations as an eye-catching pointing device. Laser pointers enhance verbal guidance given to students during surgery. The suggested mechanism of explanation is that the technology enables more precise guidance of location and identification of anatomic structures.

Red laser pointers can be used in almost any indoor or low-light situation where pointing out details by hand may be inconvenient, such as in construction work or interior decorating. Green laser pointers can be used for similar purposes as well as outdoors in daylight or for longer distances.

Laser pointers are used in a wide range of applications. Green laser pointers can also be used for amateur astronomy.Rayleigh scattering and airborne dust,star parties or for conducting lectures in astronomy. Astronomy laser pointers are also commonly mounted on telescopes in order to align the telescope to a specific star or location. Laser alignment is much easier than aligning through using the eyepiece.

Laser pointers are used in industry. For instance, construction companies may use high quality laser pointers to enhance the accuracy of showing specific distances, while working on large-scale projects. They have proven to be useful in this type of business because of their accuracy, which made them significant time-savers. What is essentially a laser pointer may be built into an infrared thermometer to identify where it is pointing, or be part of a laser level or other apparatus.

Laser pointers are used in robotics, for example, for laser guidance to direct the robot to a goal position by means of a laser beam, i.e. showing goal positions to the robot optically instead of communicating them numerically. This intuitive interface simplifies directing the robot while visual feedback improves the positioning accuracy and allows for implicit localization.

Entertainment is one of the other applications that has been found for lasers. The most common use of lasers in entertainment can be seen in special effects used in laser shows. Clubs, parties and outdoor concerts all use high-power lasers, with safety precautions, as a spectacle. Laser shows are often extravagant, using lenses, mirrors and smoke.

Lasers have also become a popular plaything for pets such as cats, ferrets and dogs, whose natural predatory instincts are triggered by the moving laser and will chase it and/or try to catch it as much as possible, but obviously never succeed.

However, laser pointers have few applications beyond actual pointing in the wider entertainment industry, and many venues ban entry to those in possession of pointers as a potential hazard. Very occasionally laser gloves, which are sometimes mistaken for pointers, are seen being worn by professional dancers on stage at shows. Unlike pointers, these usually produce low-power highly divergent beams to ensure eye safety. Laser pointers have been used as props by magicians during magic shows.

As an example of the potential dangers of laser pointers brought in by audience members, at the Tomorrow Land Festival in Belgium in 2009, laser pointers brought in by members of the audience of 200 mW or greater were found to be the cause of eye damage suffered by several other members of the audience according to reports about the incident filed on the ILDA (International Laser Display Association"s) Web site.

Laser pointers can be used in hiking or outdoor activities. Higher-powered laser pointers are bright enough to scare away large wild animals which makes them useful for hiking and camping.

Some militaries use lasers to mark targets at night for aircraft. This is done to ensure that "friendly" and "enemy" targets are not mistaken. A friendly target may wear an IR emitting device that is only visible to those utilizing night vision (such as pilots). To pinpoint the exact location of an enemy combatant, they would simply illuminate the target with a laser beam detectable by the attacking aircraft. This can be one of the most accurate ways of marking targets.

Laser pointers, with their very long range, are often maliciously shone at people to distract or annoy them, or for fun. This is considered particularly hazardous in the case of aircraft pilots, who may be dazzled or distracted at critical times.

Irresponsible use of laser pointers is often frowned upon by members of the laser projector community who fear that their misuse may result in legislation affecting lasers designed to be placed within projectors and used within the entertainment industry. Others involved in activities where dazzling or distraction are dangerous are also a concern.

Another distressing and potentially dangerous misuse of laser pointers is to use them when the dot may reasonably be mistaken for that of a laser gun sight. Armed police have drawn their weapons in such circumstances.

The output of laser pointers available to the general public is limited (and varies by country) in order to prevent accidental damage to the retina of human eyes. The U.K. Health Protection Agency recommended that "laser pointers generally available to the public should be restricted to less than 1 milliwatt as no injuries [like the one reported below to have caused retinal damage] have been reported at this power".

Studies have found that even low-power laser beams of not more than 5 mW can cause permanent retinal damage if gazed at for several seconds; however, the eye"s blink reflex must be intentionally overcome to make this occur. Such laser pointers have reportedly caused afterimages, flash blindness and glare,safe when used as intended.

A high-powered green laser pointer bought over the Internet was reported in 2010 to have caused a decrease of visual acuity from 6/6 to 6/12 (20/20 to 20/40); after two months acuity recovered to 6/6, but some retinal damage remained.anecdotal reports it received of eye injury from laser pointers.

Laser pointers available for purchase online can be capable of significantly higher power output than the pointers typically available in stores. Dubbed "Burning Lasers", these are designed to burn through light plastics and paper, and can have very similar external appearances to their low-power counterparts.

Studies in the early twenty-first century found that the risk to the human eye from accidental exposure to light from commercially available class IIIa laser pointers having powers up to 5 mW seemed rather small; however, prolonged viewing, such as deliberate staring into the beam for 10 or more seconds, can cause damage.

The UK Health Protection Agency warns against the higher-power typically green laser pointers available over the Internet, with power output of up to a few hundred milliwatts, as "extremely dangerous and not suitable for sale to the public."

Lasers classified as pointers are intended to have outputs less than 5 mW total power (Class 3R). At such power levels, an IR filter for a DPSS laser may not be required as the infrared (IR) output is relatively low and the brightness of the visible wavelength of the laser will cause the eye to react (blink reflex). However, higher-powered (> 5 mW) DPSS-type laser pointers have recently become available, usually through sources that do not follow laser safety regulations for laser packaging and labeling. These higher-powered lasers are often packaged in the same pointer-style housings as regular laser pointers, and usually lack the IR filters found in professional high-powered DPSS lasers, because of costs and additional efforts needed to accommodate them.

Though the IR from a DPSS laser is less collimated, the typical neodymium-doped crystals in such lasers do produce a true IR laser beam. The eye will usually react to the higher-powered visible light; however, in higher power DPSS lasers the IR laser output can be significant. What poses a special hazard for this unfiltered IR output is its presence in conjunction with laser safety goggles designed to only block the visible wavelengths of the laser. Red goggles, for example, will block most green light from entering the eyes, but will pass IR light. The reduced light behind the goggles may also cause the pupils to dilate, increasing the hazard to the invisible IR light. Dual-frequency so-called YAG laser eyewear is significantly more expensive than single frequency laser eyewear, and is often not supplied with unfiltered DPSS pointer style lasers, which output 1064 nm IR laser light as well. These potentially hazardous lasers produce little or no visible beam when shone through the eyewear supplied with them, yet their IR-laser output can still be easily seen when viewed with an IR-sensitive video camera.

In addition to the safety hazards of unfiltered IR from DPSS lasers, the IR component may be inclusive of total output figures in some laser pointers.

Though green (532 nm) lasers are most common, IR filtering problems may also exist in other DPSS lasers, such as DPSS red (671 nm), yellow (589 nm) and blue (473 nm) lasers. These DPSS laser wavelengths are usually more exotic, more expensive, and generally manufactured with higher quality components, including filters, unless they are put into laser pointer style pocket-pen packages. Most red (635 nm, 660 nm), violet (405 nm) and darker blue (445 nm) lasers are generally built using dedicated laser diodes at the output frequency, not as DPSS lasers. These diode-based visible lasers do not produce IR light.

In 1998, an audience member shone a laser at Kiss drummer Peter Criss"s eyes while the band was performing "Beth". After performing the song, Criss nearly stormed off the stage, and lead singer Paul Stanley ripped into whomever had been manipulating the laser light:

According to FIFA stadium safety and security regulations, laser pointers are prohibited items at stadiums during FIFA football tournaments and matches.UEFA.Olympique Lyonnais was fined by UEFA because of a laser pointer beam aimed by a Lyon fan at Cristiano Ronaldo.World Cup final qualifier match held in Riyadh, Saudi Arabia between the home team and the South Korean team, South Korean goalkeeper Lee Woon-Jae was hit in the eye with a green laser beam.2014 World Cup during the final group stage match between Algeria and Russia a green laser beam was directed on the face of Russian goalkeeper Igor Akinfeev. After the match the Algerian Football Federation was fined CHF50,000 (approx. £33,000/€41,100/US$56,200) by FIFA for the use of lasers and other violations of the rules by Algerian fans at the stadium.

In 2009 police in the United Kingdom began tracking the sources of lasers being shone at helicopters at night, logging the source using GPS, using thermal imaging cameras to see the suspect, and even the warm pointer if discarded, and calling in police dog teams. As of 2010 the penalty could be five years" imprisonment.

Despite legislation limiting the output of laser pointers in some countries, higher-power devices are currently produced in other regions and are frequently imported by customers who purchase them directly via Internet mail order. The legality of such transactions is not always clear; typically, the lasers are sold as research or OEM devices (which are not subject to the same power restrictions), with a disclaimer that they are not to be used as pointers. DIY videos are also often posted on Internet video sharing sites like YouTube which explain how to make a high-power laser pointer using the diode from an optical disc burner. As the popularity of these devices increased, manufacturers began manufacturing similar high-powered pointers. Warnings have been published on the dangers of such high-powered lasers.safety features sometimes found on laser modules sold for research purposes.

In April 2008, citing a series of coordinated attacks on passenger jets in Sydney, the Australian government announced that it would restrict the sale and importation of certain laser items. The government had yet to determine which classes of laser pointers to ban.Victoria and the Australian Capital Territory a laser pointer with an accessible emission limit greater than 1 mW is classified as a prohibited weapon and any sale of such items must be recorded.Wayne Parnell had a laser pointer directed at his eyes when attempting to take a catch, which he dropped. He denied that it was a reason for dropping the ball, but despite this the MCG decided to keep an eye out for the laser pointers. The laser pointer ban only applies to hand-held battery-powered laser devices and not laser modules.

In November 2015 a 14-year-old Tasmanian boy damaged both his eyes after shining a laser pen "... in his eyes for a very brief period of time". He burned his retinas near the macula, the area where most of a persons central vision is located. As a result, the boy has almost immediately lost 75% of his vision, with little hope of recovery.

New regulations controlling the importation and sale of laser pointers (portable, battery-powered) have been established in Canada in 2011 and are governed by Health Canada using the Consumer Protection Act for the prohibition of the sale of Class 3B (IEC) or higher power lasers to "consumers" as defined in the Consumer Protection Act . Canadian federal regulation follows FDA (US Food & Drug Administration) CDRH, and IEC (International Electrotechnical Commission) hazard classification methods where manufacturers comply with the Radiation Emitting Devices Act. As of July 2011 three peoplemischief and assault.

The "RESOLUCIÓN 57151 DE 2016" prohibits the marketing and making available to consumers of laser pointers with output power equal to or greater than one milliwatt (>=1 mW).

Laser pointers are not illegal in Hong Kong but air navigation rules state that it is an offense to exhibit "any light" bright enough to endanger aircraft taking off or landing.

During the 2019–20 Hong Kong protests, laser pointers are being used by protesters to confuse police officers and scramble facial recognition cameras. On August 6, 5 off-duty police officers arrested Baptist University student union president Keith Fong Chung-yin after he purchased 10 laser pointers in Sham Shui Po for possession of "offensive weapons". Fong said he would use the pointers for stargazing, but police described them as “laser guns” whose beams could cause eye injuries. In defence of the arrest, police said that under Hong Kong law the pointers can be deemed “weapons” if they are used in or intended for use in an attack. The incident led to a public outcry. Human rights activist Icarus Wong Ho-yin said that going by the police explanation, “a kitchen worker who buys a few knives can be arrested for being in possession of offensive weapons”. Democratic Party lawmaker and lawyer James To Kun-sun criticized the police for abuse of power. Hundreds of protesters gathered outside the dome of Hong Kong"s Space Museum to put on a “laser show” to denounce police"s claims that these laser pointers were offensive weapons. Fong was released unconditionally two days later.

Before 1998 Class 3A lasers were allowed. In 1998 it became illegal to trade Class 2 laser pointers that are "gadgets" (e.g. ball pens, key chains, business gifts, devices that will end up in children"s possession, parts of toys, etc.). It is still allowed to trade Class 2 (< 1 mW) laser pointers proper, but they have to meet requirements regarding warnings and instructions for safe use in the manual. Trading of Class 3 and higher laser pointers is not allowed.

UK and most of Europe are now harmonized on Class 2 (<1 mW) for General presentation use laser pointers or laser pens. Anything above 1 mW is illegal for sale in the UK (import is unrestricted). Health and Safety regulation insists on use of Class 2 anywhere the public can come in contact with indoor laser light, and the DTI have urged Trading Standards authorities to use their existing powers under the General Product Safety Regulations 2005 to remove lasers above class 2 from the general market.

Since 2010, it is an offence in the UK to shine a light at an aircraft in flight so as to dazzle the pilot, whether intentionally or not, with a maximum penalty of a level 4 fine (currently £2500). It is also an offence to negligently or recklessly endanger an aircraft, with a maximum penalty of five years imprisonment and/or an unlimited fine.

To assist with enforcement, police helicopters use GPS and thermal imaging camera, together with dog teams on the ground, to help locate the offender; the discarded warm laser pointer is often visible on the thermal camera, and its wavelength can be matched to that recorded by an event recorder in the helicopter.

Laser pointers are Class II or Class IIIa devices, with output beam power less than 5 milliwatts (<5 mW). According to U.S. Food and Drug Administration (FDA) regulations, more powerful lasers may not be sold or promoted as laser pointers.

In Arizona it is a Class 1 misdemeanor if a person "aims a laser pointer at a police officer if the person intentionally or knowingly directs the beam of light from an operating laser pointer at another person and the person knows or reasonably should know that the other person is a police officer." (Arizona Revised Statutes §13-1213)

Public law 264, H.P. 868 - L.D. 1271 criminalizes the knowing, intentional, and/or reckless use of an electronic weapon on another person, defining an electronic weapon as a portable device or weapon emitting an electric current, impulse, beam, or wave with disabling effects on a human being.

In Utah it is a class C misdemeanor to point a laser pointer at a law enforcement officer and is an infraction to point a laser pointer at a moving vehicle.

In September 2011, GaN diode laser modules capable of operating at 250mW (or 300mW pulse) with a heatsink were offered on eBay in the Industrial Lasers category at around US$60.

Badman, Märit; Höglund, Katja; Höglund, Odd V. (2016). "Student Perceptions of the Use of a Laser Pointer for Intra-Operative Guidance in Feline Castration". 43 (2): 1–3. doi:10.3138/jvme.0515-084r2. PMID 27128854.

Bará, S; Robles, M; Tejelo, I; Marzoa, RI; González, H (2010). "Green laser pointers for visual astronomy: how much power is enough?". 87 (2): 140–4. doi:10.1097/OPX.0b013e3181cc8d8f. PMID 20035242. S2CID 5614966.

Nakagawara, Van B., DO. "Laser Hazards in Navigable Airspace" (PDF). FAA. Archived from the original (PDF) on 16 December 2011. Retrieved 15 December 2011.

Wyrsch, Stefan; Baenninger, Philipp B.; Schmid, Martin K. (2010). "Retinal Injuries from a Handheld Laser Pointer". N Engl J Med. 363 (11): 1089–1091. doi:10.1056/NEJMc1005818. PMID 20825327.

Sliney DH, Dennis JE (1994). "Safety concerns about laser pointers". J. Laser Appl. 6 (3): 159–164. Bibcode:1994JLasA...6..159S. doi:10.2351/1.4745352.

Utah State Legislature 76-10-2501 Unlawful use of a laser pointer Archived 10 July 2008 at the Wayback Machine Most states now have similar laws to Utah"s making some uses of laser pointers (such as pointing one at a police officer or an aircraft (federal law) a crime)

If you’ve ever given a presentation in Google Slides and wished you had a laser pointer to highlight key points, you’re in luck: You can use your mouse as one. Here’s how to do it, along with two more useful tips that’ll make Slides even better and easier to use.

In this video I showed expert tips for using Presenter View in Windows with two screens. What if you only have one screen? You can still use Presenter View in Zoom as I show in this video for Windows and this video for Mac. When using Presenter View with one screen in Zoom, you use the advanced sharing mode of sharing a portion of your screen to share just the portion that contains the current slide. With only one screen you have to adapt the way you use some of the advanced features in Presenter View because you are sharing a portion of your screen and the audience will see what is in that section on your screen.

The key issue with sharing a portion of your screen in Zoom is that the audience sees everything that is displayed in that portion of the screen. If you move your cursor in that portion of the screen, the audience will see it (unlike Presenter View with two screens where moving the cursor over the current slide area does not show the cursor to the audience). This is why you need to take extra care when moving your cursor when sharing a portion of the screen in Zoom because the audience sees it if you move the cursor through the shared portion on the way to select a menu item at the top of the screen.

By default, your computer will interpret the keyboard shortcut only in the program you are using. In order to have the keystrokes interpreted in Zoom, you can either a) first click on the Zoom meeting control bar before using the shortcut, or b) in the Zoom settings check the box to make the keyboard shortcut universal so it is interpreted by Zoom regardless of what program you are using. I recommend you enable the global shortcuts for Pause and Resume. If the shortcuts interfere with a shortcut you use in a program, you can change the shortcut in the Zoom keyboard shortcuts settings.

Using the shortcut keys to access the laser pointer or drawing tools is the best way to make sure the audience doesn’t see what you are doing. Make sure the cursor is not on top of the slide before you change the pointer to one of the drawing tools. Use the tool on the slide, then move it off the slide before using the keyboard shortcut to return the cursor to the pointer. This is the cleanest appearance to the audience.

The Mac version of Presenter View does not offer this zoom option. One alternative is to first pause the screen. Then adjust the portion of the screen you are sharing so it is showing a portion of the slide. When you resume sharing the audience will see only that portion of the slide larger than before. To move to another section of the slide, drag the green selection rectangle in Zoom by using the top thicker bar. While you are moving the selection rectangle Zoom pauses the sharing automatically. When you release your mouse button Zoom shares the new portion of the slide with the audience. The audience doesn’t see you panning across the slide like the Windows Presenter View zoom feature offers, but it is an option that gives you some zoom ability. When you want to return to the regular view of the slide, pause the screen, adjust the sharing rectangle to show the full slide, the resume sharing the screen.

Dave Paradi has over twenty-two years of experience delivering customized training workshops to help business professionals improve their presentations. He has written ten books and over 600 articles on the topic of effective presentations and his ideas have appeared in publications around the world. His focus is on helping corporate professionals visually communicate the messages in their data so they don’t overwhelm and confuse executives. Dave is one of fewer than ten people in North America recognized by Microsoft with the Most Valuable Professional Award for his contributions to the Excel, PowerPoint, and Teams communities. His articles and videos on virtual presenting have been viewed over 3.5 million times and liked over 14,000 times on YouTube.

There are always colorblind people among the audience and readers. There should be more than TEN colorblinds in a room with 250 people. If you design a facility or industrial product that will be used by 10,000 people, 400 of them would be colorblinds. (assuming 50% male and 50% female.)

1Choose color schemes that can be easily identified by people with all types of color vision, in consideration with the actual lighting conditions and usage environment.

For micrographs with triple or more channels, additionally show either greyscale picture of each channel , or the combination of most important two channels in magenta and green.(example)

The majority of colorblind is the so called "red-green colorblind," with problems either in the red or green opsin gene. People with mutant red opsin gene is called protanope, and green opsin gene deuteranope.

Difficult to distinguish colors between red and green with similar intensity (brightness). The confusion occurs in somewhat symmetric manner: The differences between "green and red" and "yellow green and yellow" is especially small.

Compared to vivid colors (with higher saturation), low saturation colors are especially hard to distinguish. For example, "sky blue and pink", "gray, pale sky blue and pale green", etc.

Color names are given to the categories of colors that appear similar to non-colorblind people. This categorization may not be compatible with the color vision of the colorblind people. Thus, communication using color names are often very difficult.

With today"s digital imaging system such as confocal microscopes, CCD cameras and array imagers, it is very easy to change the colors of each recording channel. When preparing for presentation, there is no reason to stick to the color you originally used for staining. Please choose the combination of colors that is most understandable to the audience.

Even images with single staining cause problem for colorblinds. Many people present such pictures with the color of the fluorescent dye used for the staining. But there are again two problems:

Separate keys are avoided. Labels are shown directly within the drawings, connected with thin lines. This way there is no need to compare the colors of two distant objects (lines and their keys). This is often difficult for colorblinds even when the objects are only a few centimeters apart.

Thus, the improved drawing can convey enough information even without color. For example, this drawing does not lose any information when being faxed or copied in black and white.

The top graph is coded only by colors. Since pale and unsaturated colors are chosen, it is difficult to distinguish different colors It is also difficult to describe the name of each color, making it difficult for communication. Readers are asked to compare the color of the graph itself with the separate keys. This is extremely difficult for Colorblinds.

The bottom graph is the best. It uses not only colors but also various hatching. Each object is clearly distinguishable even without color vision. Again, this drawing does not lose any information when being faxed or copied.

Being friendly to colorblind people does not necessarily mean that one should not use colors. Even for the colorblinds, colors are very useful cues to distinguish different objects easily and quickly. By carefully selecting colors that are easily recognizable to people with all kinds of color vision, one can maximize the effect of her/his presentations.

2) Avoid the situation where texts and objects are obscured with the background.For example, there should be enough contrasts in brightness and saturation between texts/objects and backgrounds. Avoid the combination of colors that have the same brightness but different only in hue. For example, red characters on green backgrounds is unreadable for colorblinds. Use either bright texts/objects over dark backgrounds, or vice versa.

4) Caution when using red.For non-colorblind people, red is the bright and vivid color. But for colorblinds, it is as dull as blue or dark green. Especially for protanopes, who cannot detect long wavelength of red light, dark red appears almost as black. Thus, avoid using red characters on black backgrounds, including blackboards.Note that black text and red text look the same for protanopes. Colorblinds people, however, still feel certain ranges of reds as bright and vivid colors. Instead of pure dark red (RGB=100%, 0%, 0% or #FF.) , please use vermilion (yellowish red with shorted wavelength: RGB=100%,32%,0% or #FF2000 ), or light red (mixed with white: RGB=100%,8%,8% or #FF1414 ).

Since red laser pointers use long wavelength of light, it is often difficult for colorblinds to see where is pointed. Recently, green laser pointers becomes available, whose color is easy to see both for colorblinds and nom-colorblinds.

In 2007, LCD computer displays with built-in circuit for colorblind proof are released by EIZO/Nanao Corporation. Because the simulation utilizes the feature that is equiped only in high-end monitors, they are not cheap (but not that expensive compared with the same monitor without colorblind simulation function.) The advantage of hardware-based simulation is that the simulation is performed on the fly. One can compare images with and without simulation regardless of the software (e.g. photographs, vector drawings, PDFs, word documents, presentations, web pages, etc.). Moreover, one can also simulate movies, TV programs, and games.

2: Remember that not all colorblind people see colors as indicated in the colorblind proof. The converted views mimic the vision of the most strongly-affected types of colorblind people (dichromats). Many other colorblind people see colors in a more similar way to people with common-type color vision. Also, to compensate their problems in identifying reddish hue, colorblind people are often more sensitive to subtle differences in bluish hue, brightness, and texture of the colored objects that common-type people tend to overlook.

b.   It shall be unlawful for any person to give, sell or offer to sell or cause any person to give, sell or offer to sell a laser pointer to any individual eighteen years of age or younger.

c.   No person who sells or offers for sale laser pointers shall place such laser pointers on open display so that such laser pointers are accessible to the public without the assistance of such seller, or his or her employee or other agent, offering such laser pointers for sale, unless: (1) such laser pointers on open display are clearly and fully visible from a place of payment for goods or services or customer information at which such seller or an employee or other agent of such seller is usually present during hours when the public is invited or (2) such laser pointers are in a package, box or other container provided by the manufacturer, importer or packager that is larger than forty-one square inches. Further, it shall be unlawful to display laser pointers in any manner or to post a sign advertising the availability of laser pointers unless a notice has been posted, in a form and manner prescribed by rule of the department of consumer and worker proteciton, indicating that the sale or giving of laser pointers to persons eighteen years of age or younger is a misdemeanor.

d.   It shall be unlawful for any person twenty years of age or younger to possess a laser pointer on school premises, unlawful for any person eighteen years of age or younger to possess a laser pointer while in a public place and unlawful for any person to direct light emitted from a laser pointer into or through a public place; provided, however, that nothing in this section shall preclude:

(1)   the temporary transfer on school premises of a laser pointer to, or possession on school premises of a laser pointer by, a person twenty years of age or younger for a valid instructional, school-related or employment purpose, where such laser pointer is used under the supervision of a school staff person, other authorized instructor, employer or employer"s agent; or

(2)   the temporary transfer in a public place of a laser pointer to, or possession in a public place of a laser pointer by, a person eighteen years of age or younger, during such person"s hours of employment, for a valid employment purpose, where such laser pointer is used under the supervision of the employer or employer"s agent; or

(3)   the direction of light from a laser pointer into or through a public place by a person nineteen years of age or older, during such person"s hours of employment, for a valid employment purpose.

e.   It shall be unlawful for any person to direct light from a laser pointer at a uniformed police officer, uniformed security guard, uniformed school safety officer, uniformed traffic enforcement agent, uniformed member of a paid or volunteer fire department, uniformed emergency medical service worker or uniformed ambulance worker, or other uniformed city, state or federal peace officer, investigator or emergency service worker, or the marked service vehicle of any such individual.

f.   When a person is found to possess a laser pointer while in a public place or on school premises in violation of subdivision d of this section, it is an affirmative defense that:

(1)   such person was traveling to or from school premises, where the laser pointer would have been or was used for a valid instructional, school-related or employment purpose under the supervision of a school staff person, other authorized instructor, employer or employer"s agent, and such person had not turned on the laser pointer or displayed it in a menacing or threatening manner; or

(2)   such person was traveling to or from his or her place of employment, where the laser pointer would have been or was used during such person"s hours of employment, for a valid employment purpose, under the supervision of the employer of* employer"s agent, and such person had not turned on the laser pointer or displayed it in a menacing or threatening manner.

g.   Authorized agents and employees of the department of consumer and worker proteciton, and of any other agency designated by the mayor, shall have the authority to enforce the provisions of subdivisions b and c of this section. A proceeding to recover any civil penalty pursuant to this section shall be commenced by the service of a notice of hearing that shall be returnable to the administrative tribunal of the department of consumer and worker proteciton. The administrative tribunal of the department shall have the power to impose civil penalties for a violation of subdivision b or c of this section as follows: not more than three hundred dollars for the first violation; not more than five hundred dollars for the second violation by the same person within a two-year period; and not more than one thousand dollars for the third and all subsequent violations by the same person within a two-year period. For purposes of determining whether a violation of subdivision b or subdivision c of this section should be adjudicated as a second, third or subsequent violation, violations of subdivision b and violations of subdivision c of this section by the same person within a two-year period shall be aggregated.

Building a screen-free BCI for robotic object selection by highlighting objects in the environment removes a level of indirection for the user. However, this benefit in terms of usability comes at the price of reduced stimulus homogeneity: When optical properties across candidate objects vary—as frequently encountered in real-world environments—the differences in appearance of the laser highlighting result in different feature distributions. While this can partly be attributed to a varying salience of stimuli, it is hard to mitigate by modifying the experimental design since we do not want to constrain or exchange the objects. In principle the laser parameters could be automatically adapted to different surfaces, yet this would pose a substantial challenge in practice. Whereas vision-based approaches can model optical properties such as the diffuse reflectance of surfaces (e.g., Krawez et al., 2018), we encountered combinations of translucency as well as diffuse and specular reflections.

Hence, we decided to approach this problem from a machine-learning perspective by modeling object instances as subclasses and training separate subclass-regularized classifiers that combine data from different subclasses in a weighted manner. We achieved strong performance gains by combining multi-target shrinkage of the mean (as proposed in Höhne et al., 2016) with both subclass-specific centering using parallel transport and the state-of-the-art performance of covariance-based Riemannian tangent space classifiers. Our approach is applicable to arbitrary subclasses and experimental paradigms. Note that the information about subclasses (e.g., objects) is readily available at test time. We found that the proposed pipeline significantly outperformed the baseline in the case of relevant subclasses, while being robust to irrelevant subclasses. Notably, we could observe smaller performance gains even when distributions do not substantially differ between subclasses (e.g., homogeneous objects). Performance did not deteriorate in the presence of a large amount of subclasses (e.g., for every position q in the stimulus sequence, data not shown). The effect sizes—gains of three or more points in AUC compared to ignoring the subclass information—were substantial and are relevant in practical applications. Introspection of the learned regularization weights (Figure 7) as a measure of subclass similarity mirrors the differences in visual appearance of the highlighting (Figure 2). While ERP amplitudes differed based on the position of a stimulus in the sequence (initial vs. subsequent), using this as a subclass resulted in smaller improvements in classification performance. This indicates that the Riemannian classification pipeline may be more robust to changes in amplitude rather than ERP waveform.

Exploring possible alternative classification approaches, in additional experiments (data not shown), we found the proposed specialized (i.e., subclass-regularized) classifiers to achieve higher classification performance than using subclass-specific normalization with a global classifier: While we found that subclass-specific centering of covariance matrices using parallel transport already improved classification, performance was lower than using our proposed approach (especially with sufficient training data). While additional geometric transformations [such as rotation to another subset of the data as proposed by Rodrigues et al. (2019)] could in principle be an alternative to the convex combination of subclass means, we observed reduced performance on our data. Applying subclass-regularized LDA on features based on mean electrode potentials in suitable time intervals (as reported in Höhne et al., 2016; results not shown) performed consistently worse than using Riemannian tangent space features (which matches the results in Kolkhorst et al., 2018).

A limitation of our current approach is the assumption that we have observed all subclasses in the training data. While this would likely not hold in practice, the subclass of a novel object could be assigned either based on visual similarity to known objects or using proximity of EEG signals in covariance space. Generally, it could be useful to use clusters of objects with similar optical properties as subclasses in the presence of a large number of objects. While we performed the analyses in this paper in an offline manner, the approach is applicable online. Compared to the subclass-agnostic classifiers during the online experiments (c.f., Kolkhorst et al., 2018), the additional computational burden of centering matrices is small, hence we are confident that results would translate to an online application.

The use of screen-free stimuli is not limited to specific stimulation parameters. In this work, we opted for stimulation aimed at eliciting ERPs as different candidate objects were highlighted sequentially rather than in parallel. The two representative SOAs in our experiments indicated robustness to different stimulus parameters. It would also be interesting to evaluate parallel screen-free stimuli with a higher frequency—more closely resembling broadband (Thielen et al., 2015) or steady-state (e.g., Chen et al., 2015) visual evoked potentials—as it is likely that different optical properties would also induce heterogeneous responses in such a setting. In this work, we used a constant stimulation sequence length for simplicity, yet information transfer rate could be increased by committing to a goal once a required confidence has been reached (i.e., dynamic stopping), which would also increase robustness to non-control states (Schreuder et al., 2013; Nagel and Spüler, 2019).

The proposed cTS+reg-LDA classification approach is also applicable outside of our screen-free BCI setting. While here the problem of non-identically distributed ERP responses induced by subclasses is especially relevant, subclasses are also frequently encountered in traditional, screen-based visual or auditory stimulus presentation. For example, varying locations of stimuli or different target-to-target intervals can also lead to dissimilar subclasses (c.f., Höhne et al., 2016; Hübner and Tangermann, 2017). Furthermore, the small improvements of our approach on homogeneous objects indicate that subclass information can be helpful even when no differences between subclasses are expected. Based on the found robustness it can be applied without risking a decline in classification performance.

Considering screen-free stimulus presentation in general, we view it as a building block that can be integrated into assistive human–robot interaction scenarios. Given that a robot is available to assist the user, it can also be used to present stimuli corresponding to possible assistive actions. As examples, it can be adapted to arbitrary goals that are related to spatial locations (e.g., where to place objects or how to avoid an obstacle) or it could be used for interactive teaching of the robot (e.g., where to grasp an object). Illuminating objects with a robot makes screen-free stimuli feasible in a changing environment with novel objects, as opposed to using active light sources on candidates. Combining the screen-free BCI with computer vision and manipulation modules (c.f., Figure 3), we envision that candidate (manipulation) actions are determined based on detected object affordances or anticipated user commands in a scene (e.g., Kaiser et al., 2016; Koppula and Saxena, 2016). As actions can be translated to appropriate highlightings of the corresponding objects, our BCI paradigm can then be used to choose between the candidates. Consequently, a screen-free BCI can be seen as a disambiguation module giving users direct control in a shared-autonomy setting.

To view the pointer movements and timings you just recorded, on the Slide Show tab, in the Start Slide Show group, click either From Beginning or From Current Slide.