Hacker News Reader

Comment by energy123 | Hacker News Reader

Relevant comment about 850nm light: https://news.ycombinator.com/item?id=21042852

My wife has a "Dr Dennis Gross Red Light Mask" that has a setting for 650nm + 850nm red light. Supposed to help with aging or something but the specs match up perfectly.

Probably way too expensive for people to buy for this purpose(probably too expensive for skin care too, it's just a mask with red LED's, if I knew that's what she was buying I probably would've just made one. That's probably why she didn't tell me). Anyway, for anyone out there looking to buy a product, it's worth checking if your wife/gf already has something. Lots of products like this for anti aging as well as for hair growth

Do you think it works? You can be honest here.

Husband alarm activated:

  Danger Danger, make positive statement and redirect to how they feel about it!

$20 of LEDS stuck on a flex PCB molded to a $10 plastic mask, with a $3 power supply sold for $450.

I have been telling myself for years I need to start building an selling these things.

Thanks for the pointer!

Someone there links to this, surprisingly affordable, product: https://www.amazon.com/dp/B075F7NV56

Are there any valid safety concerns with this? Or is it just the simple check: "as long as the wattage is low enough, it's fine."

My experience with evaluating consumer medical devices ("lifestyle" and "fitness") is that what is on the box is often not what the device actually does. Besides wavelength and wattage, you would probably need to check for consistency, whether there aren't any spikes, etc. I don't know how much IR light is dangerous for the brain / what tolerances are acceptable.

More is not better. Research suggests optimal mJ/c^2/s dosages for each wavelength. Stuff on amazon is not going to be calibrated at all to dosage or even wavelength. Aside from being ineffective, there aren't dangerous side effects except prolonged exposure if staring into high intensity NIR.

Can you explain more about optimal dosages and which products deliver those dosages? We get about 0.05 J/cm²/s of infrared irradiance from natural sunlight, so we'd probably want to be at that level, or above but less than an order of magnitude above it?

One challenge is the irradiance drops off as a square a distance. So like 5 inch away vs 1 inch away is a difference of 25x irradiance.

I would not use it without proper eye protection for that particular wavelength. Staring into an infrared light will probably negatively affect your eyesight. As the eyes cannot see it, your pupil will not react and you also can't judge how bright it is.

What about putting it to the side at a 60 degree angle?

The FOV of your eyes is insane, you have usable retina more than 90 degrees off center. If you want to avoid illuminating your eyes, you need to avoid illuminating your face.

I came here to link this. @manmal was truly ahead of their time.

Reply on news.ycombinator.com