Screens and Migraines: It's Probably Not the Blue Light

Search this and you get filters, tinted glasses and night-mode settings, nearly all of it built on blue light. Blue light is the part of the explanation with the weakest evidence and the strongest marketing.

Two other properties of the same screens and the same rooms have better support, and both have the advantage of being changeable in an afternoon.

Flicker, which you cannot see and your visual cortex can

Light sources do not shine steadily. They cycle, and the rate varies enormously — older fluorescent tubes on magnetic ballasts cycle at rates most people never consciously notice, and LED sources vary depending on how they are driven.

The relevant finding is that migraine brains appear to handle this differently. In laboratory testing of flicker contrast detection, people with migraine aborted a task in which flickering screen contrast was progressively increased at significantly lower contrasts than people with no migraine history — and that held at every temporal frequency tested, from 1 Hz through 30 Hz.

That is a measured difference in tolerance rather than a self-reported one, which is what makes it worth more than the usual trigger surveys. It also explains a common and confusing experience: a room that is fine for everyone else being genuinely difficult for you, with nothing visibly wrong with it.

The practical upshot is that the buzzing strip light above your desk is a better suspect than the colour temperature of your monitor.

Glare, which is duller and probably more common

Glare is the other half, and it gets no marketing at all because there is nothing to sell.

A screen positioned in front of a bright window. A shiny desk surface throwing light back up. Bare overhead fittings with the diffuser yellowed or missing. In each case your visual system spends the day adapting between very different brightness levels, and that adaptive work is what produces the ache behind the eyes that people attribute to screen time.

The tell is that it tracks the room rather than the hours. If four hours at the kitchen table is worse than eight in a different room, you are looking at conditions rather than dose.

Changing conditions, not hours

Most advice here amounts to “use screens less”, which is unhelpful if screens are your job and untestable in any case.

Change these instead, and change them all in one go for the first pass:

• Kill the overhead fluorescent above your desk and use a lamp at eye level. This is the single highest-yield change and it costs nothing where you control the switch.
• Match screen brightness to the room rather than running at maximum. The strain comes from the difference between screen and surroundings, not the absolute level.
• Move the screen out of the direct line of a window, or drop a blind. Perpendicular to the window beats facing it or backing onto it.
• Turn the contrast of the room down in the evening — a lamp behind the screen removes the bright-rectangle-in-a-dark-room problem.
• Check the refresh rate if you have a monitor that supports more than 60 Hz, and use the higher setting.

If you work somewhere you do not control, these are ordinary requests rather than accommodations, and they cost an employer approximately nothing — how to ask for migraine accommodations at work covers how to frame them, and a colleague raising a flickering light as a maintenance issue is often faster than you raising it as a health one.

The two-week test

Everything above is a change, and a change with no baseline teaches you nothing.

Take your attack rate and your headache days from the fortnight before you change anything. Then make the changes, hold them for two weeks minimum and preferably six, and keep logging every attack and the clear days — a record with only bad days in it produces a list rather than a rate.

Two things to watch for, both of which produce false results. Screen conditions usually change at the same time as something else, because you rearranged the room or started a new job, so write down what else changed that week. And two weeks is short: a good fortnight happens by itself often enough that a single improvement is a lead rather than a conclusion. The full method, including why one variable at a time matters, is in how to track migraine triggers without fooling yourself.

On filters and tinted lenses

Some people find them genuinely useful. Some find nothing. Precision tints have a research literature that is more mixed than the marketing suggests, and general-purpose blue-blocking glasses are targeting the property with the least evidence behind it.

The reasonable position is not to dismiss them, it is to buy one thing at a time and test it the way you would test a food. Three purchases in the same month leaves you with a strong impression and no idea which item, if any, did anything.

Anything involving tinted lenses prescribed for a diagnosed visual condition is a matter for an optometrist or your neurologist rather than a shopping decision, and worth raising as a question rather than arriving with a product.

What to write down

Two fields on top of whatever you keep:

• Where you worked that day — home, office, which room
• Whether the overhead light was on

That is it. Over six weeks those two columns will do more than any subjective note about screen time, because they capture the thing that actually varies. The free printable diary has a notes column that fits both, and Migraine Journal’s per-attack notes do the same on a phone.

None of this is medical advice. Eye strain, glare sensitivity and headaches also have causes that have nothing to do with migraine, and a change in your vision, or headaches that are new or different in character, is a reason to see an optometrist or a doctor rather than to rearrange a desk.