Ultrasound gel?

[Nightbird]

I was just viewing the Painpoint Medical site, reading about their MiBo device. While i was not very impressed with the device itself, I did note they are using ultrasound gel to conduct the heat from the device through the eyelids. I'm now wondering if this concept could be applied to using a warm compress. The gel must be safe to put on your eyelids as it's used for MiBo, and also for eye ultrasound procedures. I guess the goo would get all over whatever you're using as a compress, but I put mine in the wash after each use anyway. Maybe it would make the compresses more effective. Any thoughts?

[MGD30]

Nightbird,

After doing a google search, I found the thermal conductivity of water to be about 0.563 W/(m-°K) . It was a bit difficult to find the exact value for ultrasound gel but I did find one for a high intensity phantom gel which has a thermal conductivity of 0.55 W/(m-°K). As you can see, the water and gel transfer heat at about the same rate, so you are better off using a wet compress.

An interesting fact is that the thermal conductivity of water vapor is much lower 0.016 W/(m-°K), which means that facial steamers are not nearly as effective as a wet compress.


http://en.wikipedia.org/wiki/List_of...conductivities
http://www.ondacorp.com/images/broch..._DataSheet.pdf

[Nightbird]

Thank you, MGD30! A very informative post, and very interesting about the steamers. Does this mean that those very expensive Blephasteam devices are actually less effective than a warm compress? It would certainly seem so. I'm sticking with the wet compresses.

[Rebecca Petris]

Great post MGD30. Thanks!

I have always wondered, though, when you've got a dense, flexible heat source sitting right on the lid margins, and don't really need to raise the temperature of the glands by all that much, how much difference, if any, does water actually make? Not an easy thing to study, I would imagine.

[Nightbird]

The heat needs to penetrate through both the skin and the tarsal plate in order to get to the glands, and a large percentage of it is dissipated by the blood vessels in the skin. So conductivity is important. That is also the reason Lipiflow heats from the inside and TearScience went to the trouble to patent that technology.

[MGD30]

Thank you, MGD30! A very informative post, and very interesting about the steamers. Does this mean that those very expensive Blephasteam devices are actually less effective than a warm compress? It would certainly seem so. I'm sticking with the wet compresses.

I would say that the warm compress is more effective, although there are other factors to consider. The facial steamer, I'm assuming, provides continuous steam at a constant temperature. The wet, warm compress loses heat over time (also loses heat quicker than a dry compress), so you would need to use multiple warm compresses and switch out one for another once one gets too cool. Also, some people have an issue with with warm compresses causing irritation and inflamation, so the Blephasteam type devices could work better for them.

[MGD30]

Great post MGD30. Thanks!

I have always wondered, though, when you've got a dense, flexible heat source sitting right on the lid margins, and don't really need to raise the temperature of the glands by all that much, how much difference, if any, does water actually make? Not an easy thing to study, I would imagine.

I would like to know how big of a difference, different types of compresses make as well. I wouldn't be surprised if there is already such research, unfortunately I dont have access to an academic journal database to search. Maybe someone in academia can try?

For someone that has the the proper equipment, I dont think it would be difficult to find this out. You would just need to safely, put a temperature sensor on the inside of the lid and test to see how how quick and to what degree it heats up with the different types of compresses.

[Rebecca Petris]

I think one thing it's helpful to keep in mind is... the distinction between clinical efficacy and palliative efficacy. It's so nice when they overlap, but so often they don't. That might for example be why we have a lot of steam fans here. At the end of the day when we need relief, we'll do 'what works' from a relief standpoint even if it's not necessarily 'what works' from a clinical standpoint.

Just interjecting that because the core question everyone who reads these things usually wants to know is, "Does it work??" And... the answer depends on how you define "work" (= I feel better, or it made my secretions beautifully runny and clear?), plus all the other thousand odd variations in the equation.

Back on topic though, I think there's surprisingly little research comparing types of heat application. Not surprising. I mean really, who's going to sink their dollars into research that might accidentally actually prove that rice bags work after all

[Nightbird]

Back on topic though, I think there's surprisingly little research comparing types of heat application. Not surprising. I mean really, who's going to sink their dollars into research that might accidentally actually prove that rice bags work after all

Who indeed? I'm guessing this study was jointly funded by the makers of Blephasteam and Eyegiene, whatever that is. The Eyegiene people didn't get their money's worth. Blephasteam got great subjective scores, but the objective tests (TBUT, Schirmer and gland expression) give wet towels a slight edge. I'm thinking placebo effect for the Blephasteam.

http://paperity.org/p/34971748/a-ran...eibomian-gland

If you put a wet towel between the heated rice bag and your eye, wouldn't that deliver essentially the same treatment as a heated wet towel? That would be much more convenient for travel, you wouldn't need to worry if the hotel room has a microwave. And maybe at home too, come to think of it.