In March 2008, a rare event took place at BSI (the British Standards Institution) – a British Standard was published - in fact there were two!  These days virtually all Standards published by BSI are agreed International Standards either truly International through ISO or IEC or a European Standard through CEN or CENELEC.  However on this occasion the concern of the relevant BSI Technical Committee (PS2/3) was such that they could not wait for International agreement and proceeded to publish a UK specific Standard.
What made this so important was the rapid introduction into the UK of Intense Pulsed Light (IPL) systems onto the market and the widespread installation and use of this equipment in clinics and beauty salons countrywide.  IPL equipment generates high intensity broadband incoherent light usually in the visible or near infrared wavelengths.  Specific wavelengths for use are selected by means of wavelength restrictive filters.  These systems are predominantly used in the cosmetic/beauty industry on the high street for such procedures as hair removal, the treatment of vascular and pigmented lesions and photorejuvenation (an alternative some say to the use of Botox). Although the HealthCare Commission regulates the use of this equipment through the Care Standards Act 2000 and its associated Regulations, the growth of the use of IPL systems has been (and is likely to continue to be) dramatic.

One of the current great weaknesses with using the equipment is the lack of a specification for protective eyewear for operators (and others) and guidance for the use of that protective eyewear.  Of course the Personal Protective Equipment Directive as applied in the UK requires workers and others to be protected and to use approved equipment for that purpose.  The Standards issued in March of this year provide that specification in BS 8497-1:2008 Eyewear for protection against intense light sources used on humans and animals for cosmetic and medical application – Part 1: Specification for products and guidance for the use is given in BS 8497-2:2008 Eyewear for protection against intense light sources used on humans and animals for cosmetic and medical application – Part 2: Guidance on use.

Protective eyewear for intense light sources (ILS) protects against excessive exposure to optical radiation during normal operation and foreseeable accidental exposure due to equipment malfunction or human error.  The protection includes accidental and cumulative exposure and discomfort associated with viewing bright reflections.  The specification covers optical radiation within the spectral range 180nm to 3000nm. This specification is not intended to give protection against the coherent light produced by lasers – this is covered by the standards EN207 and EN208.

An Intense Light Source (IPL) is a device incorporating one or more artificial non-laser sources of optical radiation of a wavelength described above and intended for creating biological effects in humans or animals.

Within the body of BS 8497-1, specifications are given for the definition of spectral transmittance, luminous transmittance and colour of the protective filters together with allowable material and surface defects, construction, labelling and user information.  The requirement for active filters is also defined.  These are all essential to protective eyewear manufacturers.  Of great benefit to users is the guidance given in the informative Annex of the Standard which suggests methods for determining the Filter Protective Factor (FPF) illustrating this with practical examples.  The assessments can be complex as much IPL equipment has different attachment tools each of which can allow a light of different wavelength to be emitted to facilitate the equipment’s use for several different procedures.  In these cases, the FPF is required to be evaluated so that suitable eyewear can be selected from a manufacturer’s range.

Standard BS 8497-2 gives practical guidance on the application of protective eyewear when using IPL equipment.  When working with sources of intense optical radiation heed should be taken of the European Directive 2006/25/EC – The Physical Agents (Artificial Optical Radiation) Directive.  This Directive requires risk assessments to be made and for protection to be given to those within the hazard area.

So it is not surprising that BS8497-2 also requires an assessment of the risk of injury from optical radiation when exposure is likely to be in excess of exposure limit values (ELV’s).  ELV’s are related to the wavelength of the radiation, the pulse duration or exposure time, the tissue at risk and for wavelength between 380nm and 1400nm, the size of the retinal image.  Calculations can be complex as IPL Equipment can emit a series of pulses in a broad spectrum.

Exposure below the ELV’s can cause secondary visual effects such as temporary visual impairment (dazzle).  It is well known that exposure to radiation in the near UV/blue wavelengths can induce fluorescence with the lens of the eye degrading visual performance. More serious effects are introduced if there is prolonged exposure.

Control measures require careful design and application. All persons within the hazard distance should be protected against eye or skin exposure to optical radiation above the applicable ELV’s.  It needs to be remembered that the extent of the hazard distance may vary according to the type of equipment and the optical properties of the applicators.  The same philosophy should be adopted as will all methods of risk reduction measures.  The hazard should be reduced as far as reasonably practicable by means of physical safeguards such as engineering controls.  Personal protection should only be used when engineering and administrative controls are impracticable or incomplete.

Eye protection should be included in the design specification of IPL systems so that the greatest effect of engineering controls can be achieved.

Client protective eyewear is particularly important as many procedures apply treatment close to the eye.  Consideration requires to be given to the good fit of the safety eyewear to prevent penetration of optical radiation from around the frame. Particular care requires to be taken to ensure eyewear does not overheat by absorbent radiation causing ocular or cutaneous thermal damage by contact.  The maximum temperature rise should not exceed 5oC for the duration of the treatment.

Unambiguous and robust methods of marking are essential to prevent the use of incorrect protective eyewear.  The standard offers a suggested checklist to aid the selection of appropriate safety eyewear for both clients (patients) and operators.

For operators it is necessary that the quality of the protective eyewear gives both comfort ( as this eyewear may be worn over a prolonged time) and clarity of vision taking into account the ambient lighting in the treatment environment (after all, the operator does have to be able to see what is being done!)

This standard concludes with practical examples for making assessment of the retinal thermal hazard together with further information of the filter protection factor (FPF) and luminous transmittance.

These standards are essential reading for those in control of establishments using IPL equipment and Laser Protection Advisers working in the medical/cosmetic industry.  Users of IPL will probably need to seek guidance to ensure total compliance.  Should the current proposals of the HealthCare Commission to de-regulate the use of Class 3B and 4 lasers together with IPL come to pass (the authors view is that this is unlikely) these standards will be vital to all clinics and high street beauty salons to ensure the current good safety record for use of this equipment.  Meanwhile the standard writers are taking these standards into the International arena for global adoption.guide away to Part 14.