The healing properties of light have been recognised for thousands of years. The Greeks and Romans both understood that sunlight could play a remedial role - although there was little understanding of why. That came much later when 20th century scientists developed an understanding of the light and heat waves emitted by the sun and their potential uses.

Photo thermal treatments

As early as 1903 scientists realised that light could be used for therapeutic treatment. The same year Danish physician Niels Finsen Ryberg was awarded the Nobel Prize for his work on light therapy, based on the development of a machine that could emit wavelengths similar to those of the sun.

The light spectrum ranges from ultraviolet light at 290 nanometres through visible light to the infrared range up to 2,000nm. Different parts of this spectrum have different effects on the skin. The purple lower end of the spectrum below 400nm is used to deliver Vitamin D, treat psoriasis, skin cancers and ageing. The blue light range from 400 to 500nm is helpful in treating acne, the yellow range at around 600nm stimulates collagen remodelling and the red range from 600 to 800nm assists hair growth and wound healing. These therapeutic wavelengths are delivered in medical and aesthetic therapies by purpose-specific machines for treatments that typically involve a timed exposure period. Photo thermal treatments are painless and do not cause any side effects. Eye protection is necessary during treatments.

Laser therapies

In 1917, Albert Einstein theorised on the stimulated emission of radiation, or what we commonly refer to as lasers. Today lasers are used in a multitude of products and systems from CD players to barcode scanners. Laser is an acronym for Light Amplification for the Stimulated Emission of Radiation and is used in the beauty industry for an array of treatments ranging from the correction of skin irregularities, pigmentation and wrinkles to hair reduction.

Lasers work by selecting a wavelength that is readily absorbed by the target tissue. The target tissue is heated to a temperature high enough to destroy it without damaging the adjacent normal tissue. The laser emits a single frequency of light with all the light waves going in the same direction, allowing the target tissue to absorb the maximum amount of heat. The target tissue is all important when treating skin problems with a laser. For pigmentation it is melanin, for spider veins blood and for wrinkles water. Each of these target tissues absorbs a different wavelength of light, meaning a different laser is needed for each specific problem.

Skin resurfacing

Ablative laser treatments are an extreme but effective method of treating acne and usually used only for severe cases because of the extended healing time involved. Recently a host of new-generation lasers have been developed that require only days, as opposed to weeks, of recovery time.

Always ask how new the laser is and when it was purchased. Recent models are far superior to earlier ones in terms of achieving predictable and precise results.

Fractional laser technology

Fractional laser technologies, which break up light beams to allow columns of untreated tissue to activate healing mechanisms beneath the skin's surface, have facilitated fast, easy treatments for skin conditions ranging from scars and birthmarks to wrinkles.

These lasers work by creating microscopic thermal injuries that trigger collagen production, stimulating cell renewal and plumping out the tissues while the surface of the skin remains intact. The best known of these is the Fraxel laser, and its applications include anti-ageing treatments, improving evenness of skin tone and texture, reducing pore size, the appearance of lines and wrinkles and helping reverse the effects of sun damage.

Because laser treatments use heat, a mild to moderate burning sensation is experienced during treatment and slight swelling and redness afterwards. This can be covered with makeup and normally subsides completely in a couple of days. Ablative and fractional laser treatments can be administered only by qualified cosmetic doctors. Intense pulsed light

Nikola Tesla first conceived the idea of intense pulsed light (IPL) in the early 1900s and presented his idea to the American army for defence. He believed that light energy could be launched to intercept a flying object, instantly vapourising it. After World War II a group of Russian physicists who migrated to Israel implemented the idea of using intense pulsed light in medicine, paving the way for IPL treatments.

Intense pulsed light in beauty therapy uses light wavelengths that safely target either melanin or haemoglobin in the skin. It can be used to permanently reduce unwanted hair growth, fade brown spots and cauterise enlarged or broken capillaries and port wine stain birthmarks. Some laser treatments have been developed specifically to treat rosacea.

Unlike lasers, IPL devices produce a broad spectrum of light in a range of wavelengths. The emitted light is further adjustable through the use of filters, allowing any skin colour to be treated. This versatility allows the characteristics of the light energy to be adjusted according to each patient's skin type, specific condition and location of the condition.

Another difference is in the area that can be treated in one session. Generally IPL treatment heads are up to eight times larger than the small spot produced by lasers, so treatments are quicker but not as targeted as laser. In terms of safety, the two types are similar, but with lasers both the practitioner and the patient need to use eye protection, and treatment needs to occur in an area where people can't wander in and be exposed to the light. Light from IPL systems may also be harmful to the eyes so protection should be worn for IPL treatments.

While lasers and IPL treat many of the same conditions, IPL is a single technology for a multitude of applications, from unsightly veins and birthmarks to ageing and sundamaged skin, unwanted hair and rosacea.