Fluorescent lights and headaches: the double-blind office study

Updated 2026-11-02

Quick answerIn a 1989 double-blind crossover study in offices, fluorescent tubes on conventional ballasts flickered at 100 Hz. When high-frequency electronic ballasts reduced that modulation, the incidence of headaches and eyestrain more than halved. Flicker you cannot see can still matter, so prefer flicker-free lighting and monitors.

Study details

  • Conventional ballasts: 43–49% light modulation at 100 Hz.
  • High-frequency ballasts (~32 kHz): under 7% modulation at 100 Hz.
  • Headaches and eyestrain more than halved under high-frequency lighting.

What to do

  • Ask facilities to replace flickering tubes or old ballasts.
  • Use a desk lamp you control.
  • Choose monitors that advertise flicker-free backlights.

FAQ

Can I see fluorescent flicker?

Usually not at 100 Hz, but the study found effects anyway.

Do LEDs flicker too?

Some do, depending on the driver; a 2024 study linked flicker effects to migraine history.

Sources

  • Wilkins AJ, Nimmo-Smith I, Slater AI, Bedocs L. Fluorescent lighting, headaches and eyestrain. Lighting Res Technol, 1989. Link
  • Miller NJ, Irvin L, Royer M, Strachan C. Visibility and annoyance of the phantom array effect varies with age and history of migraine. Lighting Res Technol, 2024. Link
  • Critical flicker frequency in migraine. A controlled study in patients without prophylactic therapy. Cephalalgia, 2005 (PubMed 15839848). Link

Not a medical device and not medical advice. Migraine Mode is a screen-comfort tool: it does not diagnose, treat, cure or prevent migraine or any other condition, and it does not replace a doctor. Its settings are based on studies of light, colour, flicker, patterns and motion; the extension itself has not been clinically tested. When to see a doctor.