You have been blaming your afternoon headaches on screen time. On stress. On not drinking enough water. And maybe those things are contributing.
But something else may be happening on your ceiling.
Every LED bulb runs on alternating current, electricity that switches direction 100 to 120 times per second depending on your country's grid.
Each time it switches, the light dims fractionally, then brightens. This is flicker. At these speeds, your conscious mind registers nothing. You see a steady light.
But your retina does not.
The IEEE P1789 committee found that flicker from electric light, whether visible or invisible, can be a trigger for headaches, migraines, fatigue, epilepsy.
The retina detects the oscillation even when the brain cannot consciously perceive it. The visual cortex processes this repeated signal.
Over hours, the load accumulates.
Cheap LED bulbs make this worse. Their switching power supplies are designed for cost, not stability. The ripple in their output is high, meaning the gap between the bright and dim phase of each cycle is wide.
A quality LED narrows that gap until the modulation is negligible. For flicker frequencies above 3000 Hz, the IEEE 1789 standard classifies the risk as effectively none.
Most budget LEDs operate nowhere near that threshold.
There is also a colour question. A French health report acknowledged that intense exposure to the blue light specifically in LEDs can lead to eye damage and poorer sleep patterns.
Colour rendering index, or CRI, measures how accurately a bulb represents colour relative to natural light. Budget LEDs often score below 80. High-quality LEDs score 90 or above.
Researchers have found that people with migraine are better at noticing light flicker than normal individuals. They are more likely to develop headaches.
So what can you do?
Look for bulbs rated flicker-free. Check the CRI, ideally above 90. In rooms where you sleep or read in the evening use warmer, lower-intensity light with minimal flicker.
Ritesh Bawri
Founder, Nira Balance. Harvard Medical School (Physiology) & Tufts Medical School (Nutrition). Helping people reverse lifestyle diseases through first-principles health science.