In this talk I discuss my 1-dimensional computer model which looks at the temporal evolution of the heat distribution, during and after irradiation of hair melanin. During longer pulsewidths (> 1ms) heat can ‘escape’ from the absorbing melanin into the surrounding tissues. As a consequence, the temperatures in the melanin are not as great compared… Continue reading BMLA talk 2024 – Modelling the heat conduction losses during long pulsewidth laser/IPL treatments
What is the real target in hair when treating with lasers or IPLs?
NOTE – In the first draft of this post, I made an error on my ratio calculations. This has now been rectified. As with all light-based laser/IPL treatments, we require a target (a chromophore) which will absorb the light energy preferentially. In hair, with the visible and near infrared wavelengths that we typically use today,… Continue reading What is the real target in hair when treating with lasers or IPLs?
How does fluence relate to depth in the skin?
What is the relationship between fluence at the skin surface and depth into the skin? This is very important. When we fire laser/IPL light energy into the skin, it encounters many, many, many atoms and molecules, which determines how that light will progress and where it will end up. As soon as it hits the… Continue reading How does fluence relate to depth in the skin?
Comparing laser light with IPL light energy in the skin
I often see comments online claiming things like ‘IPL doesn’t penetrate as deeply as laser’ or ‘IPL is ineffective in treating hair/blood/potatoes/whatever…’ These comments are usually never based on the science. So, here’s the science… Light is light! Hope this helps, Mike. Our next MasterClass will be held in Liverpool in June of this year.… Continue reading Comparing laser light with IPL light energy in the skin
Testing the “Neatcell Picosecond Laser Pen” device…
A laser colleague of mine sent me a lovely wee gift – the “Neatcell” pen (thanks Neil!). The company’s web site is here (it’s full of contradictions and discrepancies!!). They claim that this device is a “picosecond laser”. I’m not so sure… Firstly, picosecond lasers are not simple devices. They use a technique called ‘mode-locking’… Continue reading Testing the “Neatcell Picosecond Laser Pen” device…
Why does spot size affect penetration depth?
This is a little tricky because it’s not intuitive. We know, from both clinical tests and computer modelling, that larger spot sizes result in more energy/fluence reaching deeper into the dermis. But how does that happen? Well, it all comes down to scattering. The dermis is mostly composed of collagen fibres. These fibres are all… Continue reading Why does spot size affect penetration depth?
The ‘kill-stun-null’ zones in laser/IPL hair removal – why some treatments don’t work…
Whilst chatting to a young lady about her laser hair removal issues, I thought of a better way to explain why treatments often don’t work. I realised that we need to visualise the skin as a sequence of ‘zones’ – the ‘kill’ zone where the hairs will always be successfuly destroyed; the ‘stun’ zone where… Continue reading The ‘kill-stun-null’ zones in laser/IPL hair removal – why some treatments don’t work…
New, downloadable booklets
I am currently writing a series of ‘bite-sized’ booklets on various topics including laser/IPL treatments, laser safety, the technologies we use today and variouis other stuff. These will be uploaded to my new web site as, and when, they come along. The first two are now available: The first one is a ‘general’ introduction to… Continue reading New, downloadable booklets
Why is suppliers’ training so dismal?
I was recently asked by a lovely bunch of ladies to train them in the use of their laser, for hair removal. They all had the same device and were all having some difficulties in achieving good results. They had all been trained by their supplier’s trainers, but felt that they were not getting the… Continue reading Why is suppliers’ training so dismal?
Laser Safety Glasses and how to ‘read’ them.
Laser safety glasses must show some information on what they are supposed to protect your eyes against. This must include the wavelength(s) and the protection levels. These are to ensure that your eyes are fully and properly protected during laser procedures. This post will explain the markings you should see on our laser safety glasses.… Continue reading Laser Safety Glasses and how to ‘read’ them.
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