Today there is evidence that the light emitted by the PSiO glasses is no danger and is, to the contrary, useful to regulate sleep / wake cycles, more commonly known as ‘circadian rhythm'.

Several rumors and press articles directed against the LED Industry have indeed mentioned in the past a dangerous potential regarding the blue tones of LED lighting, and it was legitimate to ask whether the colored lights emitted by the PSiO were dangerous to human eye, especially for people with macular degeneration. Today, this is no longer relevant.

As a matter of fact, French researchers, including Serge Picaud, a researcher at INSERM and INSTITUTE OF VISION (, found that the toxicity of blue lighting tones do not depend on the light intensity but that the toxic band corresponds precisely to wavelengths of light between 415 and 455 nanometers. The wavelength used in the diodes of the PSiO are not concerned. For information, PSiO has 3 LEDs (RGB) which emit a blue light with a dominant frequency at 470 nm. This wavelength is responsible, more than any other type of light, for regulating the hormone associated with sleep, namely the ‘melatonin' (*).

A manufacturer of optical glasses, the Essilor group has also set up a type of glass to filter the "bad blue " or ‘violet blue' and ultraviolet frequencies. Those glasses also maximize the transmission of "good blue " (which is essential to chronobiology) while maintaining the transparency of glass (Crizal lenses Prevencia).

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