By Equipment Specialist, Bianca Du Preez
“Studies have shown that almost 73 % of aesthetic and medical practices utilise one or more laser machines in their clinic. This can only mean one thing: laser equipment leads to desired results (if utilised correctly of course). With a significant growth in the use of lasers in the industry, it can be overwhelming to know what laser treatment is the correct one for you. Before we go into that, let’s understand why wavelength within laser equipment is important and applicable to you.
First and foremost did you know that laser is an acronym for Light Amplification by Stimulated Emission of Radiation? So where does wavelength come in? Wavelength is the term used for energy present in the protons and is measured in nanometers (nm). Each laser targets and treats a specific biological chromophore with selective photo thermolysis. The principle of selective photo thermolysis is where a chromophore gets treated without causing collateral damage to surrounding tissue. Essentially the wavelength used, depends on the concern you are treating – e.g. when you want to achieve hair reduction (melanin) you don’t want to boil the water in your skin and cause a blister, therefore a chosen and tested wavelength is used for this aesthetic concern.
The chosen wavelength will have a different effect on how your body will absorb the energy. Commonly referred to as the Absorption curve.
I know, what a mouth full, now that the technical terms are out of the way it should make the following better to understand.
Chromophores can be divided into 3 main classifications – Water, melanin and haemoglobin (blood).
When your therapist or doctor treats you, the first step is to distinguish what you would like to achieve with the laser beam. Once they have confirmed the chosen wavelength, they also take into account how quickly that chromophore needs to absorb the energy and release the heat without causing collateral damage to other surrounding structures. Thermal Relaxation Time is the term used to describe the ability of the structure to return to baseline in a certain time. Making use of cooling methods will help to reduce the time it takes. Each biological chromophore has a size and depth variation. The greater the wavelength (1064nm) the deeper the energy that is delivered and the deeper the wavelength penetrates the gentler the delivery is.
Hair Reduction
Next time you go for your removal, pay attention to the number displayed on the device. Melanin in the hair follicle will react to a wavelength in the 600nm – 1100 nm spectrum. Melanin inside the hair absorbs the light energy, converts it to heat and ultimately damages the hair.
To achieve hair reduction we have three gold standard wavelengths in the market namely Alexandrite 755 nm, Nd:Yag 1064 nm and Diode 810 nm.
Alexandrite/ 755 nm = target chromophore melanin
Nd Yag /1064 nm = target chromophore haemoglobin (blood)
Diode /810 nm = target melanin & haemoglobin (blood)
The chromophore to treat lighter Fitzpatrick skin types (1-3) is Melanin which can be found in the follicle. Alexandrite 755nm would therefore be the best option. To treat darker Fitzpatrick skin types (4 and 5) with dark hair would be considered dangerous to treat with a 755nm as the laser would confuse the melanin in the skin and the melanin in the hair follicle. Therefore 1064 nm Nd:Yag would be used as it is colour-blind and hunts the blood vessel feeding into the follicle.
Skin Rejuvenation
Water is generally the targeted chromophore when achieving skin rejuvenation.
Fractional vs non-fractional, ablative vs non-ablative the options are endless: in simple- any thermal injury made to the skin will cause skin rejuvenation.
The differences lie amongst how long it takes for the skin to heal and what the downtime is.
When it comes to severe cases of acne scarring, surgical scarring or severe ageing, unfortunately, a more aggressive treatment protocol will have to be followed so that the laser can reach a deeper surface area. Fractional lasers like a 1550nm or ablative CO2 10 600nm lasers would generally be used in such a case.
When removing pigment or smaller skin irregularities like sun damage, fractional lasers like 1927 nm thulium Lasers have shown amazing results.
Vascular Lesions Removals
Vascular lesions are often very complex and the correct treatment plan, in my opinion, is often misjudged. To have the best possible outcome on a vein it’s important to know when it’s Oxygen rich or “poor” blood you are working with e.g., red, small and broken capillaries found around the nose, aka Cherry Angiomas, large purple or blue veins found on legs. The most effective lasers would generally be a pulsed dye laser 595 nm or a Nd:Yag 1064 nm laser as those would be the peaks of absorption for the blood chromophore.
Is it important for you as a patient to know what wavelength is being used when treated? Not necessarily. What is important, is that you fully trust your aesthetic centre’s (physician/therapist) knowledge and experience on lasers and wavelengths. And that they are equipped with quality devices that are able to deliver the necessary energy and cooling system.
With above in mind, just imagine your physician’s face when you open up the conversation on wavelengths and what you have learnt – priceless.”