We’re often warned about how dangerous small commercial lasers can be for our eyes yet technologies like FaceID projects light in our faces many times a day.
Why is FaceID safe? Because it’s low enough power or because it’s in the non-visible spectrum?
Can the non-visible spectrum be dangerous for our eyes?
In: 40
Yes. UV light is quite harmful, x rays and gamma rays too. Infra red I’m not too sure about
Short answer, yes in sufficient doses. Just about everything at a higher frequency can damage the human eye and the only reason we don’t suffer from it is because we take it in such low amounts.
For example, the single flash you get from a medical x-ray is harmless but if the doctor pounded on the button as fast as he could for a day you’d suffer a dangerous dose of radiation. Same with UV rays. A little is good for your health but too much will cause sunburns . Just imagine sunburns on the insides of your eyes.
There are two types of light outside the visible spectrum. Infrared and Ultraviolet. And those are completely different things. Things like FaceID and night vision cameras and the like use infrared. This is basically harmless to us, at least compared to visible light. It is technically possible to get too high concentration of IR light just as visible light and this may burn you. Especially the eyes as you do not have the same reflexes for IR light as for visible light. This is why powerful IR lasers have the same warning stickers as visible light lasers. However consumer products do not contain these types of powerful lasers, and if they do they are not exposed to the user.
Ultraviolet does have the same issues as IR and visible light when it comes to the powerful concentrated lasers that can burn you. But in addition to this UV light is at the lower end of ionizing radiation. This is the type of radiation which can damage tissue and cause things like radiation burns and cancer. This can happen at much lower intensities. So even non-lasar UV lights will come with warnings and shields preventing people from being exposed to it.
All waves of light are damaging in the right dosage. If I put your eyeballs in a microwave, they’ll be damaged. If I put them in front of an x-ray machine for long enough, they’ll be damaged. Or in front of a laser at any number of visible or invisible wavelengths.
Anything that the biological material of the eye can absorb will interact with that material. You get enough interactions per time frame and you’ll start doing damage. The eye is alive though and can cool itself with evaporation and blood flow so as long as the dosage stays below a threshold no permanent damage is done.
Yes. Anything from near infrared on up can damage the eye. The eye is fairly opaque to certain wavelengths (like some in the UV portion of the spectrum), so most of the damage is on the outer part of the eye, as opposed to near IR and visible light where the damage focuses on the retina.
yes. I remember working with a high power laser that was barely outside the visible range. The power is so high, the scattered reflection can blind you. As someone described it – if you go into the room without protection your sight will just turn into blackness forever.
(PhD in optics, have run ANSI safety calculations for medical implements)
There are two main ways for light to damage your retinas:
1. You can denature the proteins with high-energy wavelengths like ultraviolet light. That’s what happens when you stare at an eclipse.
2. You can burn them with ultraviolet (UV), visible, or infrared (IR) light. It’s mostly a problem with infrared because we don’t notice that the light is bright since we can’t see it.
In extreme cases you can damage them in other ways, like boiling the liquid and physically detaching the retina.
We mostly sustain damage from infrared (IR) and ultraviolet (UV) light because
1. We have a blink reflex that protects us from intense visible light. It’s very hard to get harmed by sunlight accidentally.
2. Very low frequency waves (like radio waves) don’t get absorbed by the retina, so there’s no transfer of energy.
3. While you can sustain damage from microwaves or e.g. gamma waves, we don’t run into them very often compared to UV and IR.
Lasers are especially dangerous because the your eyes are very good at focusing laser light down to a tiny pinpoint. All of that light energy gets concentrated in a tiny area, which then gets heated very quickly. IR lasers are more dangerous than visible because we don’t blink, but visible can still be dangerous if they’re high enough power.
EDIT: spelled out acronyms
Any frequency of EMR can do damage if there’s enough of it, simply by causing heat when it’s absorbed.
Visible frequencies can do damage beyond that because the retina are necessarily sensitive to them and overloading them can damage them.
Higher frequencies (Ultraviolet and up) can do additional damage beyond causing heat by ionizing atoms which leads to changes in the chemicals containing those atoms. This is what causes sunburn from ultraviolet and radiation poisoning from X-Rays and Gamma Rays. Sunburn is essentially skin deep radiation poisoning. Getting sunburnt eyes is not something you want.
Yes, and it’s significantly more dangerous for exactly that reason.
I work with powerful infrared lasers, and if there was one shining in your eye, you wouldn’t know it until you went blind.
Can a bullet hurt if a rock thrown at you can’t? Yes. One has more energy. Just like x-rays etc have more energy than visible light.
We’re often warned about how dangerous small commercial lasers can be for our eyes yet technologies like FaceID projects light in our faces many times a day.
Why is FaceID safe? Because it’s low enough power or because it’s in the non-visible spectrum?
Can the non-visible spectrum be dangerous for our eyes?
In: 40
Yes. UV light is quite harmful, x rays and gamma rays too. Infra red I’m not too sure about
Short answer, yes in sufficient doses. Just about everything at a higher frequency can damage the human eye and the only reason we don’t suffer from it is because we take it in such low amounts.
For example, the single flash you get from a medical x-ray is harmless but if the doctor pounded on the button as fast as he could for a day you’d suffer a dangerous dose of radiation. Same with UV rays. A little is good for your health but too much will cause sunburns . Just imagine sunburns on the insides of your eyes.
There are two types of light outside the visible spectrum. Infrared and Ultraviolet. And those are completely different things. Things like FaceID and night vision cameras and the like use infrared. This is basically harmless to us, at least compared to visible light. It is technically possible to get too high concentration of IR light just as visible light and this may burn you. Especially the eyes as you do not have the same reflexes for IR light as for visible light. This is why powerful IR lasers have the same warning stickers as visible light lasers. However consumer products do not contain these types of powerful lasers, and if they do they are not exposed to the user.
Ultraviolet does have the same issues as IR and visible light when it comes to the powerful concentrated lasers that can burn you. But in addition to this UV light is at the lower end of ionizing radiation. This is the type of radiation which can damage tissue and cause things like radiation burns and cancer. This can happen at much lower intensities. So even non-lasar UV lights will come with warnings and shields preventing people from being exposed to it.
All waves of light are damaging in the right dosage. If I put your eyeballs in a microwave, they’ll be damaged. If I put them in front of an x-ray machine for long enough, they’ll be damaged. Or in front of a laser at any number of visible or invisible wavelengths.
Anything that the biological material of the eye can absorb will interact with that material. You get enough interactions per time frame and you’ll start doing damage. The eye is alive though and can cool itself with evaporation and blood flow so as long as the dosage stays below a threshold no permanent damage is done.
Yes. Anything from near infrared on up can damage the eye. The eye is fairly opaque to certain wavelengths (like some in the UV portion of the spectrum), so most of the damage is on the outer part of the eye, as opposed to near IR and visible light where the damage focuses on the retina.
yes. I remember working with a high power laser that was barely outside the visible range. The power is so high, the scattered reflection can blind you. As someone described it – if you go into the room without protection your sight will just turn into blackness forever.
(PhD in optics, have run ANSI safety calculations for medical implements)
There are two main ways for light to damage your retinas:
1. You can denature the proteins with high-energy wavelengths like ultraviolet light. That’s what happens when you stare at an eclipse.
2. You can burn them with ultraviolet (UV), visible, or infrared (IR) light. It’s mostly a problem with infrared because we don’t notice that the light is bright since we can’t see it.
In extreme cases you can damage them in other ways, like boiling the liquid and physically detaching the retina.
We mostly sustain damage from infrared (IR) and ultraviolet (UV) light because
1. We have a blink reflex that protects us from intense visible light. It’s very hard to get harmed by sunlight accidentally.
2. Very low frequency waves (like radio waves) don’t get absorbed by the retina, so there’s no transfer of energy.
3. While you can sustain damage from microwaves or e.g. gamma waves, we don’t run into them very often compared to UV and IR.
Lasers are especially dangerous because the your eyes are very good at focusing laser light down to a tiny pinpoint. All of that light energy gets concentrated in a tiny area, which then gets heated very quickly. IR lasers are more dangerous than visible because we don’t blink, but visible can still be dangerous if they’re high enough power.
EDIT: spelled out acronyms
Any frequency of EMR can do damage if there’s enough of it, simply by causing heat when it’s absorbed.
Visible frequencies can do damage beyond that because the retina are necessarily sensitive to them and overloading them can damage them.
Higher frequencies (Ultraviolet and up) can do additional damage beyond causing heat by ionizing atoms which leads to changes in the chemicals containing those atoms. This is what causes sunburn from ultraviolet and radiation poisoning from X-Rays and Gamma Rays. Sunburn is essentially skin deep radiation poisoning. Getting sunburnt eyes is not something you want.
Yes, and it’s significantly more dangerous for exactly that reason.
I work with powerful infrared lasers, and if there was one shining in your eye, you wouldn’t know it until you went blind.
Can a bullet hurt if a rock thrown at you can’t? Yes. One has more energy. Just like x-rays etc have more energy than visible light.
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