Is the optical sensor light safe for children?

Yes. Halo Lytt uses green and red LED light, which is the same optical sensing method used by Apple Watch, Whoop and Oura.

It is low-power visible light resting against the skin. There is no infrared, no ultraviolet and no laser involved. This technique, photoplethysmography, works by measuring how much light is reflected back as blood volume changes beneath the skin, and it is the standard approach across consumer wearables for adults and children alike.

The device is also FCC and CE certified. If your child has a specific photosensitivity condition, check with your doctor first.