What are FL-41 migraine glasses and how do they work?

FL-41 Q & A

  • FL-41 Glasses are glasses that are fitted with a special filter that blocks out certain colour wavelengths.  Some people refer to them as migraine glasses, light sensitivity glasses or photophobia glasses. The filter was given the code name FL-41 by Birmingham University after extensive testing in the UK back in the 1990s.

    Migraine headaches are a huge problem and can be very debilitating. Migraines affect 1 in 7 people and are three times more common in women than men. Believe it or not, Migraines are more prevalent than diabetes, epilepsy and asthma combined.

  • To understand how FL-41 lenses work the first thing we have to understand is that we don’t see with our eyes, we see with our brain. The image that we look at is received by the brain as electrochemical signals. It’s believed that migraine sufferers find certain colours create error signals that trigger or intensify a migraine.  

    Much research has gone into why colours can affect our health and wellbeing. But much is still not understood as to why the brain reacts with regards to wavelengths of colour. What we do know is that when we block certain colours, organise or change the way in which the brain receives signals, we can get dramatic effects. A simple example of that would be Polarised lenses or 3D lenses. Many Doctors are aware of the benefits of the FL-41 filter and will recommend them to patients. You may wish to consult yours. We would always recommend that before treating any medical condition you seek the advice of your eye doctor (ophthalmologist) or GP.

  • Sadly not, we are all unique individuals; we might block a certain colour for one person, whilst the same colour may help another with dyslexia. There is no test whether someone will benefit from FL-41, just like back in the 90s, it’s trying it and see. On a positive note, Birmingham University assembled over 500 migraine sufferers and over 80% benefited. It’s got to be worth a try, start with the tester. If you wear prescription lenses the tester will fit over normal size spectacles. Your only loss, if they don’t help, is the return postage; as soon as the glasses are returned you will receive a full refund.

    The natural tendency for a migraine attack is to head for the nearest dark room. This will help, of course, you are removing all light and colour. But that’s just treating the symptom and not the cause. Another common practice is to wear very dark glasses, this has the same effect. The graph below shows the difference between a pair of dark grey lenses in the red line against the FL-41 filter is the blue. You can clearly see the dramatic difference in the mid frequency.


  • There are a range of other conditions that can benefit from using the FL-41 filter

    • Blepharospasm
    • Blink Frequency
    • Photophobia
    • Sensitivity to fluorescent lighting
    • Motion sickness
    • Night-time driving