Your website design could be triggering migraine attacks.
Is this a trivial issue? Should you care?
There's heaps of information about designing accessible web sites for people with disabilities, because for government agencies in many countries, this is mandatory.
But I haven't seen anything in WCAG 2.0 about migraine sufferers, so I'm speaking up on their behalf.
There are at least 34 million in the USA alone. Among adults of all ages, migraine is one of the top 20 causes of disability expressed as years of healthy life lost to disability (The World Health Report 2001, WHO)
More facts about the prevalence of migraine in the world
This is not a pity party but a fact storm
That's an awful lot of pain.
Certain types of visual stimulation often trigger migraines. These include features you might be using on your website, for example:
Why should this be?
Here's my non-scientific answer. (I figured this out after realising that bright lights, black-and-white stripes, and crazy patchwork literally give me migraines.)
The usual sequence of events:
Sometimes the brain jumps the gun. When shown anything that resembles the visual aura (e.g stripes, shimmery lights), brain thinks "OK, got the message, I know what to do next!' . . . and goes into automatic migraine. We are conditioned (like Pavlov's dogs) to have migraines.
We turn down the screen brightness, we add antiglare screens, and perform 100 other anti-migraine rituals. We hit the back button at the drop of a hat. The other day I did something a little weirder: I placed my hand over half the computer screen, hiding the menu of a certain web page. It shimmered, you see. I started to get that here-comes-a-migraine feeling, and automatically protected myself.
Therefore delete the horribles. Please remove those loops of pattern and colour, and anything else that's suspect. As for the vile flashing, jiggling ads all over About.com, they have made me and others abandon that portal forever.
If in doubt, try your website out on a migraine sufferer. You won't have any trouble finding one. We are legion.
But as for finding one willing to test your zig-zaggy staircasey flashy shimmery strobey scintillating rapidly moving geometric sort of website ... fat chance.
Note: This article originally appeared in a slightly different form on Quality Web Content, where some of Rachel's historic articles lurk.