Why One Laser Cannot Do Everything
A clinic with six lasers is not being extravagant. Light of one colour is absorbed by one thing and passes through another, and there is no wavelength that is simultaneously ideal for a red vessel, a brown spot, a dark hair and a rough texture. The number of devices in a practice is, in a real sense, the number of different problems it can address properly rather than approximately.
A clinic with six lasers is not showing off. Light of one colour is soaked up by one thing and passes straight through another, and there is no single colour of light that is ideal for a red vein, a brown spot, a dark hair and rough texture all at once. The number of machines a practice owns is, in a real sense, the number of different problems it can treat properly rather than roughly.
Why One Laser Cannot Do Everything: the essentials
The short version
A laser is defined by what its light is absorbed by
What a laser can do is decided by what soaks up its light.
Haemoglobin, treated with wavelengths around 532 to 595 nanometres, or 1064 for depth
Blood. Treated with particular colours of light, and a deeper reaching one for vessels further down.
Melanin, treated with pigment-selective wavelengths and very short pulses
Pigment. Treated with light that pigment soaks up, in extremely short flashes.
The skin itself, treated with 2940 or 10600 nanometres for resurfacing
Resurfacing lasers are soaked up by the water in your skin, which is how they take a surface off.
Nothing, or a burn: too little absorption, or absorption in the wrong place
Either nothing at all, or a burn: the light is not soaked up, or it is soaked up in the wrong place.
Choosing the device is most of the treatment; the rest is settings and technique
Choosing the right machine is most of the treatment. The rest is settings and technique.
Three families, three targets
Three families, three targets
Almost every aesthetic laser belongs to one of three groups, defined by what absorbs its light. Vascular lasers target haemoglobin. Pigment lasers target melanin. Resurfacing lasers target water, which is to say the tissue itself. That is the whole taxonomy, and it explains most of the confusion in the field.
Almost every cosmetic laser belongs to one of three groups, and the groups are defined by what soaks up their light. Some are aimed at blood. Some are aimed at pigment. Some are aimed at the water in the skin itself, which is how resurfacing works. That is the whole classification, and it explains most of the confusion in this field.
Because the groups are defined by absorption, they are not interchangeable. Pointing a resurfacing laser at a thread vein does not treat the vein; it treats the skin over it. Pointing a vascular laser at a brown spot achieves very little, because the pigment absorbs poorly at that wavelength. This is not a limitation to be engineered around. It is the principle the machines work by.
Because the groups are defined by what soaks up the light, you cannot swap them around. Point a resurfacing laser at a thread vein and you do not treat the vein, you treat the skin above it. Point a vein laser at a brown spot and very little happens, because pigment barely soaks up that particular light. This is not a shortcoming waiting to be engineered away. It is the principle the machines run on.
A fourth consideration cuts across all three: depth. Longer wavelengths generally reach deeper. So the choice is two-dimensional, what you want to be absorbed by, and how deep you need to reach, and a device is a point in that space rather than a general-purpose tool.
There is a fourth thing that cuts across all three: depth. Longer wavelengths generally reach further down. So the choice has two dimensions, what you want the light to be soaked up by, and how deep you need to get. A machine is one point in that space, not an all purpose tool.
Why the same wavelength behaves differently
Why the same light can behave completely differently
Two devices at the same wavelength can do entirely different things, because the other variable is time. Nanosecond and picosecond pulses deliver their energy so quickly that the effect is largely mechanical, shattering a pigment particle rather than cooking it. Millisecond pulses heat.
Two machines using the same colour of light can do entirely different things, because the other variable is time. Flashes measured in billionths of a second, or thousandths of that again, deliver their energy so fast that the effect is more like shattering than cooking. Flashes measured in thousandths of a second heat instead.
This is the difference between a pigment laser and a hair removal laser using overlapping wavelengths. Hair removal wants to heat a structure the size of a follicle, so it uses millisecond pulses. Tattoo and pigment removal wants to break up particles measured in fractions of a micrometre, so it uses pulses many thousands of times shorter. Same target material, different physics, different machine.
That is the difference between a pigment laser and a hair removal laser that use overlapping colours of light. Hair removal wants to heat something the size of a hair root, so it uses the longer flashes. Tattoo and pigment removal wants to shatter particles a fraction of the width of a hair, so it uses flashes many thousands of times shorter. Same target material, different physics, different machine.
Fractional delivery adds a further axis. Rather than treating the whole surface, the beam is split into thousands of microscopic columns with untreated skin between them, which changes healing time dramatically without changing the wavelength at all.
Treating in dots adds one more choice. Instead of covering the whole surface, the beam is split into thousands of microscopic columns with untouched skin between them. That changes healing time enormously without changing the colour of the light at all.
What a combined platform actually buys you
What a machine with two settings actually gets you
Devices that offer more than one wavelength are not marketing. A platform combining, say, 755 and 1064 nanometres lets the operator choose the shorter wavelength for its stronger absorption in lighter skin, and the longer one for its depth and its relative safety where there is more pigment in the skin.
Machines offering more than one colour of light are not just a sales feature. Combining a shorter wavelength with a longer one lets the operator use the shorter one, which is soaked up more strongly, for lighter skin, and the longer one, which goes deeper and is safer where there is more colour in the skin, for everyone else.
The clinical value is that the person does not have to fit the machine. Where a practice has only one wavelength, the honest options are to treat everyone with it, which is unsafe for some, or to decline the ones it does not suit. More wavelengths means more people can be treated properly, which is a different claim from more wavelengths means better results.
The point is that you do not have to fit the machine. If a practice owns only one kind of light, their honest options are to treat everybody with it, which is unsafe for some people, or to turn away the people it does not suit. More options means more people can be treated properly. That is a different claim from more options means better results.
What this means when you are choosing
What this means when you are choosing
The useful question is not which laser is best. It is which laser is right for this problem, in this skin, at this depth, and does the practice have it.
The useful question is not which laser is best. It is which laser is right for this problem, in this skin, at this depth, and does this practice actually have it.
A clinician who names the device, explains what it is absorbed by, and says why it suits your particular concern is describing a plan. One who describes a single machine as suitable for everything is describing a purchase. Both may be perfectly competent, but only one of those answers tells you anything.
A clinician who names the machine, explains what soaks up its light, and says why it suits your particular concern is describing a plan. One who describes a single machine as good for everything is describing a purchase. Both may be perfectly capable, but only one of those answers tells you anything.
It is also reasonable to ask what happens if the first choice is not working. A practice with a range can change approach; a practice with one device can only change the settings, and there is a limit to how far that goes.
It is also fair to ask what happens if the first choice does not work. A practice with a range can change approach. A practice with one machine can only change the settings, and there is a limit to how far that gets you.
Questions patients ask
Is a newer laser always better?
Is a newer laser always better?
Not necessarily. Newer devices often add convenience, speed or comfort, but the underlying physics of what absorbs which wavelength has not changed. A well-maintained older device used skilfully for the right indication outperforms a newer one used for the wrong one.
Not necessarily. Newer machines often add speed, comfort or convenience, but what soaks up which light has not changed. A well kept older machine used skilfully for the right job beats a newer one used for the wrong job.
Can one treatment fix redness and brown spots together?
Can one treatment fix redness and brown spots at the same time?
Sometimes partially, with broadband light sources that emit a range of wavelengths. For pronounced problems of either kind, a device selected for that specific target usually gives a better result, and the two may be treated in separate sessions.
Sometimes partly, using a light source that gives out a wide range of colours at once. If either problem is significant, a machine chosen for that specific target usually gives a better result, and the two may be treated in separate sessions.
Why can my friend have a treatment that I cannot?
Why can my friend have a treatment that I cannot?
Usually skin tone, tanning status, medical history or the nature of the lesion. Settings and devices safe for one skin type can be unsafe for another, and a responsible practice will decline rather than adapt around it.
Usually skin tone, a recent tan, medical history, or what the spot actually is. Settings and machines that are safe for one skin type can be unsafe for another, and a responsible practice will say no rather than try to work around it.
Does a bigger spot size mean a stronger treatment?
Does a bigger treatment head mean a stronger treatment?
A larger spot penetrates deeper for the same energy density because less light is scattered out of the beam at the edges, and it treats faster. It is a tool for reaching depth and covering area, not a straightforward measure of strength.
A bigger head reaches deeper for the same amount of energy, because less light scatters away at the edges, and it covers ground faster. It is a tool for reaching depth and covering area, not a simple measure of strength.
How many lasers does a practice actually need?
How many lasers does a practice actually need?
Enough to cover the targets it treats: something for vessels, something for pigment, something for resurfacing, and ideally more than one wavelength for hair removal so a range of skin types can be treated safely.
Enough to cover the targets it treats: something for blood vessels, something for pigment, something for resurfacing, and ideally more than one option for hair removal, so a range of skin tones can be treated safely.
Where to go next
Talk it through with a physician first.
Every plan starts with an assessment of your skin, your anatomy and what you actually want to change.
This page is general health information, not medical advice. It cannot tell you whether a treatment is right for you. Approved uses, risks and results differ from person to person, and product labelling changes. Ask us at Dermatology and Laser Centre about your own situation, or make an appointment, and seek urgent care for any serious symptom.
