Laser safety management (medical and cosmetic applications)
'Core of knowledge' course notes

Safety Controls

The risk assessment will determine the most appropriate controls to effectively manage the risks from intense light. Examples of typical controls are listed below.

 Written policies and procedures

Written procedures form part of the training system and help ensure consistent working practices.

 Designation of a "controlled area"

The 'controlled area' is the area in which it is possible for intense light to cause harm. In medical and cosmetic applications, it is typical to designate the treatment room or theatre as a controlled area. Note that this only applies when the hazard is present (i.e. the machine is on). Many of the controls below are introduced to,

a) Manage the risks to the operators and patient/clients in the controlled area
b) Prevent harmful levels of light escaping the controlled area
c) Prevent unauthorised access to the controlled area

  Design features of the machine

Design features of the machine may only allow exposure in certain directions for example, or when the laser device is in contact with the skin. Other features may include a key (or pin) control to prevent unauthorised access, shielded fibres, shielded foot-switches and emergency stops.

  Training and instruction

Trained competent staff are absolutely vital and also a legal requirement. The provision of training and instruction can be achieved in a number of ways and typically include;

- Applications training (how to use the machines and perform treatments): This is typically achieved by practical 'hands-on' training, backed up with written instructions.

- Safety training: Typically achieved through safety briefs/talks and written instructions ("local rules", see below).

  Workplace culture

Maintaining a good health and safety 'culture' in the workplace is important.

  Safe working practices

Again, established safe working practices and clear policies and procedures are an effective control.

  Measures to confine the light to the room

May include blinds/covers on windows, addressing double door gaps etc.

  Warning signs

Placed at the entrances to a defined area, these deter unauthorised entry. Illuminated signs can also be connected to the laser power supply, which activate automatically when the laser is in use.

See also: Laser/IPL warning signs examples and information


Example of illuminated warning signs. Note the difficulty in positioning these at eye level.

  Plume controls

These may include; 'Smoke' evacuators and face masks. The term 'plume' or 'Laser generated airborne contaminants (LGAC)' is sometimes used.

Personal protective equipment (PPE)

Eyewear, gloves and face masks.

  Control of access

Controls may include, warning signs, barriers, door interlocks etc. Consideration may be given to locking of the treatment room doors.

Reflections

The vast majority of medical and cosmetic lasers are 'Class 4', meaning that even reflections from rough/matte surfaces are potentially hazardous. We therefore often treat every surface in the room as if it were a mirrored surface and control exposure to the beam through administrative procedures and eyewear.

We would generally recommend the removal of any reflective surface which may further concentrate the intensity of the beam or increase it's Nominal Ocular Hazard Distance (NOHD). In practice, reflective objects of this design are rare.

The above statement is sometimes misinterpreted as simply "reflective surfaces", which causes confusion over light fittings and chrome door handles etc. It also may lead people to assume that only reflections from mirrored surfaces are hazardous.

Eyewear

Whilst most industrial users of lasers manage to enclose laser beams, medical and cosmetic laser users almost always have to resort to protective eyewear.

Eyewear should be:

- CE marked
- In a good state of repair
- Stored correctly
- Kept clean and hygienic
- Offer an appropriate level of attenuation at the appropriate wavelength(s)

It is a legal requirement that staff should be trained in the correct use of the eyewear. Typically, eyewear labelling is not user friendly and this carries a significant risk of using the wrong type.

For patient/client use, fully opaque shields are available. These should be used for treatments close to the face.

See: patient/client eye-protection

Laser Eyewear

Laser eyewear is wavelength specific. It is therefore very important that firstly, the correct eyewear is obtained and secondly, where different lasers are used, measures are taken to prevent accidentally using the wrong ones. These measures may include extra labeling and separate storage. Staff training should feature in these controls.

Visibility with laser eyewear is often good, as only a small part of the visible spectrum needs to be blocked out.

It is accepted practice to also protect the eyes of unconscious patients as the eye-lid alone is not generally accepted as a suitable laser barrier.

Laser eyewear is usually tested to a relevant safety standard (EN 207 in Europe, ANSI Z136 for the US).

Intense Pulsed Light (IPL) Broadband Eyewear

IPL eyewear is potentially problematic. This is because the equipment emits light over a broad spectrum and blocking against all visible light impairs vision (similar to wearing sunglasses indoors).

Whilst safety standards do exist for IPL eyewear (e.g. EN 8497: 2008), the vast majority of eyewear supplied in Europe and the USA, seems to use the welding shade scale. Typically,

- Welding Shade 3 (typically light green) are provided for the operator.
- Welding Shade 5 (typically dark green) are provided for clients for treatments away from the face.

These do not offer anywhere near the attenuation of laser goggles (which often reduce the laser light by a millionth!) and instead block out the light to the same degree as dark sunglasses (~60%).

'Automatic shields' are also available which offer normal vision but are equipped with a fast acting 'shutter' against bright light from IPL equipment.

The visibility problem and lack of suitably specified eyewear means that the issue of personal protective equipment for IPL devices is less than ideal.

It is worth mentioning that due to the highly divergent nature of the light from an IPL device, reflections will not generally be a problem, as the IPL head would probably have to be pointed straight at the eye to cause damage. However, there is usually a fair amount of 'leakage' from the sides of the crystal which can be unpleasant for those operating the device over a long period.

Warning signs

Whilst it is unlikely that someone entering a room where laser treatments are being carried out will receive an eye strike (lasers are either directed onto or inside the patient), unauthorised entry could cause a distraction to the laser operator who could make a mistake. Ideally, signs should be displayed at eye level.


Signs affixed to treatment room door. This is not ideal as the hazard is not present all the time.

Illuminated warning signs are commonly used in hospitals as these can be wired so as to light up when the laser is switched on. Modern illuminated warning signs tend to use LED which largely removes the requirement to constantly check bulbs for failure.

A common mistake is to permanently display signs stating words to the effect of "laser, do not enter". Treatment rooms are only designated as a "controlled area" whilst a laser/IPL session is underway. Signs should be removed when the machine is not being used. However, for rooms where the machines are more or less in constant use, the examples below could be used.



See: Laser/IPL warning signs examples and information

In cases where eyewear is stored outside the room, blue "eyewear must be worn" signs can be displayed on the outside of the entrance. However, this situation is rare in a medical/cosmetic environment and so there is usually no need to display this sign.

Under the UK Health and Safety (Safety Signs and Signals) Regulations 1996, the following is required:

- Signs are maintained in good condition

- Comprehensible and relevant information on the measures to be taken in connection with safety signs is provided to employees.

- Employees receive suitable and sufficient instruction and training in the meaning of safety signs and the measures to be taken in connection with safety signs.

- The effectiveness of a sign must not be adversely affected by placing of too many signs too close together.

Written Safety Procedures (Local Rules)

The term "Local rules" is sometimes used to describe general procedures for the safe use of laser and other intense light equipment. They typically include information such as,

- Description of the hazard
- Definition of a designated working area
- Key contacts/personnel
- Key safety instructions
- Correct use of Personal Protective Equipment (PPE)
- Meaning of signage
- Emergency procedures
- Refer to specific operating procedures for the actual activity

Some general tips are given below for anyone writing a 'local rules' document.

1. Identify the target readership and the key safety points you want them to take on board.

2. Where possible, aim to cover all rooms and lasers into a single concise document.

3. In the same way, aim to standardise the controls. For example whilst it isn't strictly necessary to cover windows for CO2 lasers, it may be less confusing to include this as a universal control.

4. Ensure that understanding is checked rather than ask staff to just read and sign.

5. Use plain English and avoid specialist terminology and acronyms as much as possible.

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