Can the light outside the human visible spectrum damage our eyes?

Question

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

Answer 1

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.

Answer 2

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.