The unit is UV-free. If you do not stare directly into the light at close range, there is no risk of eye damage (says Philips in the extensive and well-to-understand manual. The unit has in addition to a power supply and an internal battery, which unfortunately can not be substituted (Lithium Ion Battery ). Thus, it can also go on trips and help if necessary to better survive the jet lag.
Depression, seasonal affective disorder and or Winter Blues are disorders that should be treated with medical assistance and not on your own with the Philips device; under a doctor's guidance can be helpful but the unit certainly. It should be noted here is that drugs can greatly increase the photosensitivity.