Special glasses developed by Canadian company may cut perils of the night shift

Shift work exacts a huge toll, leading to punishing sleep disruptions and an elevated risk of illnesses that range from breast cancer to heart disease. Although the reasons for the adverse health effects are currently unknown, some researchers say the graveyard shift has at least one unique hazard: It exposes people to large amounts of light at night, a time when humans are supposed to be shrouded in darkness. Canadian company Zircadium Corporation has developed special glasses that may reduce the adverse affects of this type of exposure.

Zircadium Protective Eyewear products prevent melatonin suppression and cortisol elevation, and prevent repeated harmful alterations to the biological clock. Certain types of dark sunglasses could be worn to achieve near the same effect, but would be unsafe and impractical for any work environment.

Being exposed to specific wavelengths of light at night causes melatonin supression, cortisol elevation and harmful alterations to the body's biological rhythms. According to the developers of Zircadium Protective Eyewear, over time, these can lead to health problems including cancer, heart disease, diabetes, depression, and sleep disorders. The company, which is headed by a professor of medicine and an optometrist,  has discovered that only a narrow band of wavelength of light is responsible for melatonin and cortisol abnormalities at nighttime. Zircadium Protective Eyewear effectively blocks these wavelengths that cause problems for rotating shift workers, while still allowing maximum light transmission through the custom designed Zircadium lenses.

Zircadium technology was developed by Bob Casper, MD, a professor of medicine at the University of Toronto and an optometrist, Jonathan Spilkin, OD. The technology was commercialized into eyewear products at the beginning of 2009.

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