After reading through some of the research, something glaring pops out to me. We have been focusing on LED's, but what about halogens? There does not seem to be any consensus or knowledge of what is better between the 600nm and 900nm range.
LED advantages:
A specific frequency is used (may be good or bad as indicated below). Low heat. Can be directly compared so some studies, although none that I have seen are for rosacea.
LED disadvantages:
One potential problem with the LED is that it is peaky. The more peaky, the more chance of failure in my opinion. The % activated cells can be very specific to wavelength. Therefore, unless you are right at the right frequency, you may not be doing a great job. LED's come in certain frequencies that are not necessarily the optimum for biological purposes. Relatively high cost. Also, some units appear to be putting out a paltry amount of energy to the target. This should have little effect on anything but your pocket book. Cannot obtain a full band of energy level and as indicated above, noone knows what the proper frequencies are, if there are any. Peaks for # of cells activated occur at 620nm, 680nm, 760nm, and 820nm.
Halogen advantages:
A broad spectrum is released and therefore you would cover blue light (for better or worse), yellow (who knows?), red, and near infrared. Therefore, if the LED that was being used "missed" the right frequency because it was too peaky, the halogen should cover it. Also, a lot of energy can be output at a relatively cheap cost. Many studies I have seen have very high energy levels, far higher than the typical LED devices we use. The halogens can come closer to some of the levels and covers 620nm-900nm..something the LED cannot do.
Halogen disadvantages:
Heat is bad for rosacea and these can generate a lot of heat. But this can be mitigated with good deisgn. Also, you are getting a broad spectrum. This may be good or may be bad. The UV can be filtered out easily though and is largely blocked by the glass in the halogen. The ultraviolets can be filtered out, but this takes more effort. Blues...well it has been said that blue can aggrevate rosacea. I am not convinced of this and I have not seen anything that would indicate this of yet. This may be a significant problem for some though. For some with an acne component or if the blue helps with p&p (unknown) this can significantly help as the acne study found the blue was very effective at killing acne causing bacteria. Peter said he was able to tolerate the blue and red lamp.
This being said, exactly what is the fascination with LED's? Convenience? less risk because it is low energy? because NASA studied it? something else?