Acne Rosacea: [rosacea] Re: Dr. David J. Goldberg: Combining Light-Based Treatments & Topica

Hi Matt,

No worries. I didn't think you sounded unappreciative at all.

Thanks for this additional information. I'll have to read through it
a couple more times to completely digest it. And I completely
agree with you about the need for more research. Let's keep a watch
out for any studies (preferably in pubmed or medical journal), and
we'll add them to the RSRP as they are published.

Hang in there...

Dan

--- In rosacea-support@yahoogroups.com, Matthew I <mtthw_i@...> wrote:
>
> Dan, once again, I never meant to sound unappreciative, it was
extremely considerate that he has taken the time out to answer some
questions. I must have been out of place by expecting more. I just
thought he could of referenced some of his material that he is making
these judgements on, for example some studies he has conducted (if he
has) or research he has come across, or anything to support what he
has said. Some good scientific support material, not just statements.
But it just seemed to be another person saying that LED therapy is
`good'.
>
> You said
>
> "One last thing. Potentially the difference between the home based
> units and the more powerful medical quality units is in how frequently
> treatments must be administered. It appears based on posts that I've
> read from users of home based units, that they seem to work best with
> more frequent use, whereas the medical quality units seem to allow
> more infrequent treatments. Just a thought..."
>
> Most of the treatments that I have seen listed in the various
studies, including the NASA study, list their treatments in Joules per
square centimetre. As you would probably already know, A joule is a
measure of a Watt Second, Therefore to rewrite what you have said
above in other terms, you can receive the same amount of Joules by
receiving a higher power level for a shorter amount of time, as a
lower power level for a higher amount of time.
>
> What I was trying to say in my previous e-mail is that the
characteristic operation of an LED dictates the amount of light output
you can receive from it regardless of the drive current. As you
provide more current to an LED, the unit heats up and the efficiency
of the LED drops off as more of the power is lost as heat and not
light. LED's are normally supplied with a data sheet that states their
optimum drive current, beyond which, too much heat is generated and
the light output is lost. Scroll down and Look at `Figure 2 – Emitter
Characteristics – a) LED' for a graphical representation of my poor
wording.
>
> http://www.fiber-optics.info/articles/LEDs.htm
>
> So there is a limit to the light output of an LED, and as I said
before, unless there is some special High light output LED that is not
commercially available, then any LED light output levels would be able
to be replicated by a standard person building a unit at home as you
can purchase power sources many many times the thermal limiting drive
current of an LED.
>
> I understand what you mean about his need to be cautious and
speculative. I was expecting systematic scientific evidence after
viewing his name associated with being a specialist in laser and LED
therapy when maybe only anecdotal evidence currently exists.
>
> Thank you for the references, I think we have discussed these
before. The second reference refers to a laser so It's hard to compare
power levels of a Coherent Linearly polarised device to an Incoherent
Randomly polarised device (LED).
>
> Looking back over all the links we have seen to the clinical studies
in Pubmed, I think there is a little confusion somewhere. LLLT can
refer to Low Level Laser Therapy and Low Level Light Therapy, where
Low Level Light Therapy can encompass LED Therapy as it is a form of
light. However, all the clinical studies Reference LLLT as Low Level
Laser Therapy.
>
> All of the clinical links in the rosacea resources reference a low
level laser and not an LED. Maybe it could be better to split it up
into Low Level Laser Therapy and LED Therapy?
>
> With this aside, It seems that the only clinical study on LED's that
we can possibly use as a benchmark is the NASA study.
>
> http://www.lighttherapyproducts.com/LEDNasastudy.html
>
> You mentioned you don't know how they compare to home units. I don't
know if they can be compared at all. But if you had to make a
comparison, from the example given previously
>
> "with a power density of 31.3 mW/cm(2) in 42 sec
> significantly reduced TNFalpha level to 50.2 (95% CI, 49.4-51.0), p <
> 0.01 units/mL versus control.":
>
> http://www.ncbi. nlm.nih.gov/ entrez/query. fcgi?db=pubmed&
cmd=Retrieve& dopt=Abstract& list_uids= 16503786& query_hl= 25&itool=
pubmed_DocSum"
>
> 31mW in a period of 42 seconds is the equivalent of 1.302 Joules.
>
> This is the best I'd be able to do…
>
> The following is a link to the data sheet of the Near Infra Red
LED's that I ordered.
>
> http://www.avagotech.com/assets/downloadDocument.do?id=1846
>
> If you scroll down to the `Radiant Optical Power' in the parameter
field in the table, you can see it emits 19mW with a Forward Drive
Current of 50mA and 38mW with a forward Drive current of 100mA.
>
> Using a 100mW drive current you would get 38mW Radiant Optical
power. The Power levels, IF comparable, between Coherent Linearly
polarised device to an Incoherent Randomly polarised device are
relatively similar. BUT we are talking about different animals here.
>
> With a typical voltage drop of 1.5V across each LED, a standard
240V/12V AC/DC 4 Amp power supply (Around 50 bucks from your local
electronic store) could supply around 480 of these LEDs which could
cover a significant area.
>
> Once again though, that is comparing the power levels of a laser to
an LED.
>
> Clearly more studies need to be done on LED therapy. It is all too
vague.
>
> Matt.
>
>
>
> Hi Matt,
>
> You're absolutely welcome. And you're right in that we do owe Dr.
> Goldberg a big thanks for taking the time to answer some of our
> questions to the best of his ability. I personally was very happy he
> took the time to answer our questions as you'd be surprised how few
> researchers and doctors are willing to do so. And of course I always
> want to know more, but still, his answers reconfirmed some of my own
> opinions on LLLT.
>
> As for some of your questions though, I've found in my admittedly
> limited interactions with medical researchers and doctors that they
> are a very cautious group. They rarely seem to speculate, and they
> nearly always use terms like "evidence seems to suggest" when
> answering questions about mechanisms of action, etc.
>
> I certainly cannot put words in any of these researcher's and doctor's
> mouths, but I personally use terms like this when answering questions
> about studies I've read, etc as I'd absolutely hate to give a
> definitive answer to someone and then find another study later on that
> suggests yet some other answer. This seems to particularly possible
> when the science or technology is in its early stages of use and
research.
>
> To answer some of your questions though, based on my own readings of
> the studies in pubmed related to LLLT devices, studies do seem to
> suggest that, particularly red/near infrared LLLT devices are
> antiinflammatory and antioxidant in nature, affecting TNF-a levels and
> thus other cytokines and enzymes that are involved in inflammation as
> well as superoxide dismutase levels which is key in clearing the
> reactive oxygen species (ROS) that are responsible for cleaning up the
> oxidants products of inflammation. See the RSRP for more info on this:
>
> http://rosacea- research. org/wiki/ index.php/ Red_LED_Lamps_
%26_Other_ Forms_of_ Low-Level_ Light_Therapy
>
> As for the quality of light output, the following study also on the
> RSRP page above mentions that reduction of TNF-a is LLLT dose
> dependent, and a 650-nm Ga-Al-As laser "LLLT dose of 0.11 Joules
> administered with a power density of 31.3 mW/cm(2) in 42 sec
> significantly reduced TNFalpha level to 50.2 (95% CI, 49.4-51.0), p <
> 0.01 units/mL versus control.":
>
> http://www.ncbi. nlm.nih.gov/ entrez/query. fcgi?db=pubmed&
cmd=Retrieve& dopt=Abstract& list_uids= 16503786& query_hl= 25&itool=
pubmed_DocSum
>
> How this compares to the home units, I unfortunately don't know.
>
> Hopefully additional studies will shed more light on these questions
> in the future...
>
> I hope this helps some. Hang in there...
>
> Dan
>
> Send instant messages to your online friends
http://au.messenger.yahoo.com
>
> [Non-text portions of this message have been removed]
>