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.
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.
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.
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.
