I have tested the device twice and then each get eye pain, although I do not just use a tinted goggles, but these have also made entirely impervious. The eyeglass rims I sealed with foam. The light has come by anyway and very bright and disappear when you come near the eye with the device head. A report by the University of Ulm, which I found on the Internet, according to can not be excluded by the LEDs eye damage. I have therefore sent the device back.