The Fluorescent Fatigue

Fluorescent tubes with magnetic ballasts don't shine continuously: they flicker at 100 hertz, twice the mains frequency. Invisible to the eye, this flicker is captured by the visual system and associated, in some, with headaches and eye fatigue.

Massively adopted in the mid-20th century for its efficiency and uniformity, fluorescent lighting equips offices, schools, and administrations. Complaints appear quickly: eye strain, irritability, end-of-day headaches. Fluorescent tubes with magnetic ballasts don't shine continuously: they flicker at 100 hertz, twice the mains frequency.

The main cause is flickering. With a magnetic ballast, the tube turns off and on a hundred times per second in Europe. In 1989, Arnold Wilkins's work showed that high-frequency electronic ballast lighting reduced office headache frequency by about half. Invisible to the eye, this flicker is captured by the visual system and associated, in some, with headaches and eye fatigue.

Incomplete spectrum and color temperature of these lamps accentuate discomfort. The passage to electronic ballasts then to LEDs has pushed back the problem without eliminating it: poor LED control can reintroduce comparable flickering.