Hand Pointer

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The time taken to recover from these effects will vary for different individuals and will also be dependent on the ambient light level at the time of exposure. Medical attention should only be sought if afterimages persist for hours, or if a disturbance in reading vision is apparent. 8. PHE advice Lasers are also used in domestic products where the laser can be ‘seen’ such as medical devices, and even toys. Laser pointers or pens have also found their way into the home and are often described as ‘toys’. However, some of these ‘toy laser pens’ have been found to be more powerful than is acceptable for unrestricted use and have the potential to cause eye damage and other harm. The advice from PHE takes account of the current British Standard for laser safety, and the technically equivalent European and International Standards. The British Standard provides advice on the use of lasers for demonstrations, displays and exhibition and states that only Class 1 or Class 2 devices should be used in unsupervised areas unless under the control of experienced well-trained operators.

Devices intended for the toy or novelty market can be of different shapes, for example a toy sword. Laser pointers which are larger in size and more importantly have a high power output are very common and inexpensive today. The size of the batteries used in a laser pointer may give some clue to the radiant power. However some laser pointers powered by AAA batteries are still powerful enough to cause life changing eye injuries. 4. Laser safety standards At home, lasers can be found in many modern appliances such as in computers, laser printers, DVD and Blu-Ray® players. In these appliances the consumer would have no access to the laser in normal use. Examples of Class 3R laser products include some laser pointers and some alignment products used for home improvement work. 5.7 Class 3B The optical radiation produced for lighting is said to be highly divergent, that is the light spreads out rapidly as the observer moves away from the bulb. It is this property which allows the illumination of large areas using a single light bulb. In contrast a laser produces optical radiation over a very narrow wavelength band, so narrow that the laser is referred to as a monochromatic or single wavelength source. A comma separated list of URLs to custom cursors. Note: Always specify a generic cursor at the end of the list, in case none of the URL-defined cursors can be used

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When the radiation emitted by a source can be detected by the eye and produces a sensation of vision, it is referred to as light. Lighting devices such as the compact fluorescent, LED or incandescent electric light bulbs produce optical radiation comprising of many different wavelengths. Their light is perceived as white light, and the bulb emits fairly equally in all directions. Lasers produce radiation with unique properties. It is these properties that distinguish laser radiation from the optical radiation produced by more familiar sources such as the sun or the common household electric light bulb. Class 4 lasers are high power devices, usually needing a mains power supply. Class 4 lasers are used for specific applications in research, medicine and industry. They are also used in as well as the entertainment industry. Historically Class 4 lasers required a mains power supply. However today handheld battery powered Class 4 laser pointers are common. The misuse of lasers, predominately laser pointers or pens, reported in the press has highlighted concerns over the safety of these devices from a number of perspectives.

Lasers are now widely used during the course of our daily lives. They can be found at home, in the workplace and they are used for many different applications. Lasers are a valuable scientific tool in material, pharmaceutical and forensic research.They play an important role in the areas of medicine and industry, as well being used for entertainment purposes since the mid-1960s. Class 3R laser products are higher powered devices than Class 1 and Class 2 and may have a maximum output power of 5 mW or 5 times the AEL for a Class 1 laser product. The laser beams from these products exceed the MPE for accidental viewing and can potentially cause eye injuries, but practically the risk of injury in most cases is relatively low for short and unintentional exposure. The risk is limited because of natural aversion behaviour for exposure to bright light for the case of visible radiation and by the response to heating of the cornea for far infrared radiation.Class 1M laser products are usually products that produce beams with a large diameter. Therefore, only a small part of the whole laser beam can enter the eye. As for a Class 1 laser product, they are safe for the naked eye under reasonably foreseeable conditions of operation. However, these laser products can be harmful to the eye if the beam is viewed using magnifying optical instruments. Although the risk of a permanent eye injury from a laser pointer up to Class 3R may be small, an individual receiving even a transient eye exposure from a laser pointer will experience a bright flash, a dazzling effect, which is likely to cause distraction and temporary loss of vision in the affected eye and possibly afterimages. Therefore, these laser beams should not be pointed at people. A consequence of this is that high power devices can present a hazard over considerable distances, often many kilometres. However, there are exceptions to these general points: some lasers produce optical radiation over a wide wavelength spectrum and some produce widely divergent beams.

Laser pointers emitting light with the laser wavelength which is closer to the eye’s peak response are therefore capable of producing the adequate visual stimulus, such as aversion response, at lower radiant powers. A laser is assigned to a particular class when the measured emission level exceeds the AEL for all lower laser classes but does not exceed the AEL for the class assigned. For example, a laser will be assigned as a Class 3R laser product when the maximum measured accessible emission level exceeds Class 1, Class 1M, Class 2 and Class 2M AEL values but does not exceed the Class 3R AEL. If product mislabelling is suspected, or there is doubt over the classification of a product then measurements should be carried out in accordance with the requirements of the British Standard to determine the actual laser class to which the device should be assigned. There is no simple test available to the general public to determine the radiant power of a laser product. A visual inspection of the laser product or its laser output will not provide any indication of the appropriate class for the device.PHE’s predecessor organisations were involved in the initial development of these Standards and PHE continues to work with the technical standards committees responsible for maintaining these documents. Incorrectly labelled laser pointers are common. Examples include laser pointers that are marked Class 2 (or output power is marked as less than 1 mW), but are actually Class 3B or even Class 4. A number of eye injuries, especially to children, have occurred from the use of Class 3B and Class 4 laser ‘pointers’. The majority of these lasers are bought from the internet rather than on the high street, while some were bought on overseas holidays. The AEL values are in turn based on Maximum Permissible Exposure ( MPE) levels. An MPE is a level of laser exposure which it is believed an individual could be exposed to without incurring an injury. An MPE may therefore be considered as a maximum safe level of exposure. MPE levels are specified for both the eye and skin as a function of the wavelength of the laser radiation and the duration of exposure. These MPE values are internationally agreed. The classification scheme for lasers indicates the potential risk of adverse health effects, where the higher the class number, the greater the laser radiation hazard posed by the laser. In practice, the risk also depends upon the conditions of use, exposure time and the environment. However, potential risks may or may not actually lead to adverse health effects, so with the help of classification, users may select appropriate control measures to minimise the risks. Class 4 laser products have an output power greater than 500 mW (half a watt). There is no upper restriction on output power. Class 4 laser products are capable of causing injury to both the eye and skin from direct exposure and reflections also may be hazardous. Class 4 laser beams also present a fire hazard. Lasers used for many laser displays, laser surgery and cutting metals may be Class 4 products.

Laser pointers sold in the UK should be classified in accordance with the current British Standard [footnote 1] on laser safety. This document specifies requirements for the manufacturers of laser products to ensure that the risk of accidental exposure is minimised through the use of engineering control features and product labelling, and by specifying minimum requirements for the supply of product information to allow for their safe use.

The response of the human eye is wavelength dependent and peaks at around 555 nm, the response decreasing as either end of the visible spectrum is approached (400 nm to 780 nm). As a result, if laser pointers are compared at 3 different wavelengths (670 nm, 635 nm and 532 nm) but at the same radiant power, the brightness as perceived by the eye will be approximately in the ratios 1 : 10 : 30.