Task 1 – Safety

Some types of PBM, when used incorrectly, can lead to pain and damage. At best, used incorrectly, or with an ineffective dose, there will be no therapeutic benefit. Therefore, it is essential that all operators of PBM equipment are suitably trained before administering PBM to animals. 

Through this course you are learning the essential information so that you can become an informed operator of PBM. Although we give you advice and guidance for practical application, you should still seek manufacturers training before using any specific piece of equipment. This is because each piece of equipment is different and in order to be safe and effective, you need to know the ins and outs of the equipment you are using. 

There are however, some safety guidelines that should be adhered to and precautions and contraindications to be aware of. 

Hazard to eyes

There is one absolute contraindication for class 3b and class lV laser therapy and that is eye exposure. One of the benefits of LED therapy over laser therapy is that LED can be safely used over the eye so it is indicated for the treatment of eye conditions. 

Wavelengths of 400-780nm and near infrared 780-1400nm are in the retinal hazard region of the visible light spectrum. Maximal permissible exposure (MPE) is the level of laser radiation that an unprotected person may be exposed to without adverse biological effects in the eyes or skin occurring. MPE is dependent on wavelength, exposure time and whether the pulse is constant or pulsed. 

Eye protection should be worn by the therapist, the animal and anyone else in the treatment area. It is important to understand that laser light by reflection can also cause damage to the eyes so the treatment area should be scanned for reflective surfaces (mirrors, stainless steel etc) and they should be covered.  Jewellery that may have reflective properties should also be removed and covered. 

For small animals, most of the laser manufacturers provide eye protection. Covering the eyes of horses and other large animals can be more difficult to achieve and sometimes inventive methods need to be created. Material such a dark thick towelling can be used to shield the eyes or a cupped hand for protection. 


It is normal for the animal to be inquisitive when the laser is first applied. They may want to investigate. This should be discouraged and treats can be a good distraction. Another way to overcome this, when the animal is particularly inquisitive is to have a little habituation time with the device off until they lose interest. Introduce them to it and let them have a sniff. They usually get bored with it and go back to their hay net or other source of food to keep them occupied such as a licky mat. 


Hazard to skin


One of the main objections to the increase in the use of high level lasers in veterinary treatment is the potential to cause harm to the animal through photothermal damage to the skin. It is a legitimate concern so we must address it. 


Class 3b lasers and LEDs are not considered hazardous to the skin. Class lV lasers however are. It is essential that any operator using the equipment has been trained by the manufacturer and knows the specific safety features of the unit. 


Application techniques 


Class 3b lasers and LEDs are held in a position for a length of time before the head is moved to the next position. In contrast, class lV laser treatment heads need to be moved constantly to avoid excessive heat build up. Other ways to reduce the chances of photothermal effects are:


  1. Pulse the light – this reduces heat build up but also increases treatment time. 
  2. Reduce the power density and increase the treatment time (keeping the total joules the same) however, reducing the irradiance may reduce the effectiveness of the treatment.
  3. Moving the treatment head further away from the skin – however this only works by increasing reflection and reducing irradiance, so you would be better off to do what is suggested in point 2 and keep the contact. 


Safety features of equipment and skill of the operator  


If you are considering investing in a laser, there are now some impressive safety features on the equipment which include warning lights in the treatment head when the operator is moving too slowly. These can be very valuable. 


However, the best way to avoid the possibility of any damage is to pay attention!! The operator should be sensitive to behavioural signs of the patient. Laser treatment should be a pleasant experience and should not cause any pain or discomfort. So if the patient is telling you otherwise then listen. You cannot rely only on the machine pre-set protocols as every animal reacts differently. The owner can also be very distracting so politely explain that you need to concentrate when delivering the treatment and may not be able to properly engage in conversation until it has finished. When teaching students in the clinical setting it has been my observation that the most common mistake when delivering lasers or ultrasound, both which have the potential to damage tissue, is to start talking and stop moving! 


I am not going to discuss all of the general safety concerns when treating and handling animals as I am presuming you are already experienced with that. But just remember that it may take a few sessions for the animal to become accustomed to the equipment and the treatment and this might be something you need to explain to the owner.