FL-41 Lenses: No, They’re Not All the Same

Written by:

FL-41 Lenses: No, They’re Not All the Same

FL-41 is a lens tint that has been shown to reduce the impact of migraine attacks in clinical studies. But what does FL-41 tint look like? Are all FL-41 glasses the same? The answer is a resounding no.

An early research project from the University of Utah Medical Center evaluated whether patients were getting the same benefit from therapeutic lenses (or lenses with FL-41 tint) from different vendors. Surprisingly, the study found wide variations in the quality, lens color, spectral characteristics, and optical densities of lenses purchased from different optical shops and laboratories.

Each line on the graph below represents FL-41 lenses from 5 different vendors.  The light shows how much light passes through the lens at different light wavelengths. As you can see, they vary significantly.

Comparison of Different FL-41 Lenses From Multiple Vendors

Here are pictures of different FL-41 migraine lenses on the same model and in the same lighting. The color of the lens ranges from rust, to purple, to hot pink. Again, significant variation.

Comparison of FL-41 lenses on the same model in the same lighting.

Where Did FL-41 Originate From?

FL-41 has a long and complex history. The technology has been in development since the 1980s and began at the University of Cambridge. Researchers were seeking a solution for individuals who were bothered by fluorescent lights. This was the original FL-41 tint, but it was quite different from what we have today. Dr. Peter Good, a neurophysiologist at Birmingham and Midland Eye Centre, read Wilkins’ research and saw an opportunity for additional applications of the FL-41 tint. This set off a chain of events that led to the precision tint for photophobia and migraine glasses that we have today.

In early 1990 Dr. Kathleen Digre of the University of Utah began recommending the FL-41 tint to some of her patients. In 1998, Axon’s own Dr. Bradley Katz, also of the University of Utah, was impressed with his colleague’s, Dr. Digre, success in using the tint to treat light sensitive patients. He began offering the tint to his own patients who suffered with migraine and some showed significant improvement. Fast forward to today and Dr. Katz has been instrumental in updating the lens design, increasing its effectiveness. The FL-41 tint has undergone several improvements and the numbers speak for themselves. It works for many who have migraine or are light sensitive.

The journey of migraine glasses FL-41 map.

How Are Axon Lenses Different?

As you saw in the first few graphs, the level of variation of generic FL-41 tint is wide.  Axon Optics brand name SpectraShield is shown to be effective and consistent compared to the major variation in generic lenses. Here are some of the differences you’ll see when you take a closer look:

  • Lens Testing: We’ve tested our proprietary Axon lenses with over 500 people using clinically validated surveys. We found that nearly 90% of these people experienced a decrease in light sensitivity and migraine. On average the impact of light sensitivity was reduced by 38%. Migraine days reduced by 24%.
  • Lens Coatings: Axon applies over 10 premium coatings on each side of its lenses to reduce glare, scratches, and smudges. This is a $100-$150 value if purchasing a similar coating through your optical shop. The Axon lens coating has less than 0.5 reflectance which is crazy low!
  • More Good Light: You don’t want to wear dark lenses inside as you’ll dark adapt your eyes — think how painful it is to come out of a Movie Matinee into bright sunlight. Axon lenses let 20-70% more good light into your eye than generic lenses that have been released after Axon launched.
  • Continued Research: Axon Optics was founded by a neuro-ophthalmologist, photonics researcher, and optical entrepreneur. My partner, Dr. Katz, has treated literally thousands of patients with light sensitivity and/or migraine. We use profits from Axon Optics to fund additional research for new products related to migraine and light sensitivity.
  • Correct Color:  Generic lenses are red, rust, purple, rose, orange, green, etc. It can be difficult to know what you are getting out there, which is why we’ve actually tested our lenses as described above.
  • Extras: You receive an eyeglass case, microfiber pouch, and a 1-year warranty. All non-prescription frames have a 100% money-back guarantee and a no-questions-asked return policy within 60 days. Feel free to try them out.
  • You can see hundreds of user experiences for insight into these lenses. If you really want to dig in, here is a long, but relevant history on the use of tinted lenses for migraine and light sensitivity.
Axon Spectrashield FL-41 lenses let more good light in that generic FL-41 lenses.

How Should I Choose A Therapeutic Lens?

Look at the research and consider the source. Axon Optics was founded by researchers at the University of Utah. One of the founders, Dr. Bradley Katz, is a neuro-ophthalmologist who has worked with thousands of patients. He has been recommending and perfecting therapeutic eyeglasses for patients with light sensitivity for over 15 years.

The Axon lenses, called Spectrashield FL-41™, have been used by tens of thousands of people and have been shown to reduce the impact of migraine in over 90% of users. Our SpectraShield FL-41™lens is proprietary, and has been fine-tuned over the last 20 years many times by Dr. Katz. Each lens comes with premium coatings that block glare and prevent finger smudges and scratches.

Axon Optics is the most advance light sensitivity FL-41 lens on the market.

Here is some feedback from an optical shop that is recommending Axon Eyewear: “I did a quick in-office test of [various vendors of FL-41].  Your tint won, especially with the office people who suffer from migraine headaches.”

Conor writes “I was recommended Fl-41 lenses, by my General Practitioner to treat my Blepharospasm and recurring monthly migraines. I have to be honest, I was not expecting the effect I’ve been getting. Light change no longer has any/ to very little impact on my eyes whether it’s UV or LED. As for my migraines, I usually go through a 6 hour ordeal, starting with dull eye pain that turns into full blown severe left hemisphere cranial pain, into the night, causing me to be sick. They don’t fully end the migraine but they minimize the symptoms, and the fact that they can deter it, is a true life changer.

The first time putting these glasses on was at work during a migraine with nausea. Literally within a second or two the nausea was gone along with the sharp pain portion of the migraine. After 35 years of fighting migraines I’m still finding it hard to believe these work as well as they do. I realize that everyone’s different, but if your one of the lucky ones where these FL-41 lenses work, they are pretty amazing.”

Try Axon SpectraShield Lenses

Try Axon FL-41 spectrashield lenses.

Don’t choose generic lenses. Not all FL-41 lenses are created equal. Get the trusted name in therapeutic eyewear. Check out our stylish frames now at our shop.

  • Axon FL-41 Glasses With Black Frame
    Product on sale
    $229 $99
    Product on sale
    $199 $85
    Product on sale
    $249 $119
  • Send In Your Frames For Custom Lenses


Blue light glasses for kids? Here's what the science says.

3 Credible Blue Light Glasses for Kids (and One Big Caveat)

Just like adults, kids tend to be exposed to many hours of screen time per day, between school work, TV, gaming, and smartphones. If you’ve ever worried about ...
Read More
Migraine glasses reviews

Migraine Glasses Reviews: 17 In-Depth Success Stories

Axon Optics makes glasses for migraine and light sensitivity, and they have helped thousands of people find relief. In fact, about 85% of users say our glasses reduce ...
Read More
Learn what lab results say about the best migraine glasses

Best Migraine Glasses Revealed in Actual Lab Study (2022)

We did it. We now know which migraine glasses are the best. If you’re wondering how, we first asked ourselves the following questions: From a science standpoint, what ...
Read More

24 thoughts on “FL-41 Lenses: No, They’re Not All the Same

  1. Grant Rutherford says:

    I currently suffer from Blepharospasm and use fl41 tint (orange)

    Do you have the clear tint available as yet


    • Virginia says:

      Hi Grant! Our tint isn’t clear, but we are continuously re-formulating our tints to appear lighter and less pigmented in appearance while providing the same or greater levels of protection. Our SpectraShield proprietary tint filters out the portion of the light spectrum which has been proven to bother light-sensitive people. We hope you’ll try our current version, which is lighter and less pigmented in appearance than earlier versions. You can try it risk-free – please read our Return Policy for details on how to trial our product for one week. If it doesn’t help, you can return a non-prescription lens in our frame from a full refund minus shipping costs.

  2. vewwall says:

    I would like the Spectra Shield FL-41 lenses to fit over my regular glasses when inside due to sunlight and fluorescent lights.. I don’t see where to order them now. I thought I saw them for$100.
    Thank you, Veva

  3. Kate Koltun says:

    Do you have a glass that goes from somewhat light to dark in the same pair of glasses? I suffer from severe photophobia both indoors and outdoors (the worst) due to severe migraine. I want to buy the correct pair for myself.

    • Lori Glover says:

      A Transitions lens can be a good option for some people. They do darken outside and double as a pair of sunglasses. The darkening transitions element within the lens won’t impede your regular vision, indoors or out. However, it is important to know that transitions only darken when directly exposed to UV light. They do not darken in bright indoor light or inside cars. Even outside it will not feel as dark as sunglasses or our outdoor tint. The baseline indoors is a very light pink tint. Transitions may take up to 5 minutes to fully “transition” from indoors and outdoors.

      Transitions are more reactive or transition faster in cold weather. Indoor temperatures and warm outdoor weather will be slower. Also, our SpectraShield FL-41 tinted lenses with premium coatings will be comparably slower than other transitions that are not tinted or coated. Transitions are available without the coatings if you prefer, but most customers opt for 2 separate indoor and outdoor frames.

  4. Renae says:

    Is there a special style that meets most healthcare required PPE in eyewear? I work in the operating room and under constant bright fluorescent lights, adding spotlights, fiberoptic, etc and need something to help with my light sensitivity with migraines.

    • Lori Glover says:

      If you need peripheral coverage, because light sources are all around you, I recommend trying the Wrap 7C or Flex Curve. If you wear prescription glasses, you can try the Cover Rx over them. If you don’t like those styles, the Construct has significant peripheral coverage also. If the tint is effective, we can then discuss custom frames. Feel free to email [email protected] for additional assistance.

  5. Janet says:

    Are the F-41 lens available in prescription for near, farsighted and stigmatism problems. I am at the computer for 8 hours and the colors, graphs, spreadsheets (lines) tires my eyes and I am squinching my eyes often.

  6. Howard Diamond says:


    I need the fl41 sunglasses, clip on only.
    This is to use over my prescription eye glasses with prism lenses?
    Currently, I have only one pair and sending u my glasses would be
    difficult for me. How do I get ur clipons locally?


    • Lori Glover says:

      If you already have the frame and the clip on piece, we can do a lens replacement for you. This is our Send In Your Frame option. You will need to send both the frame and the clip on to us. We do not manufacture the clip on pieces. You can also consider the Cover Rx frame which fits over your prescription. Feel free to email [email protected] or call 779-379-2966 for more information.

  7. Heather says:

    Will you be bringing back the Dalliance frame in pink and purple? I have an ordinary pair of fl-41 tinted glasses but I have to wear them 24-7 so I’d love a pair that is more fun.

  8. Jo-Ann Ferriman says:

    Are there different t levels or depth of colour when ordering FL-41 tints? Or just one option? Tha ks

    • Lori Glover says:

      Our tinted lens options are based on use. The indoor lens is for indoor activities like shopping, working on the computer, or watching tv. The outdoor lens is more comparable to traditional sunglasses recommended for being outside exposed to bright sun and UV rays. Feel free to email [email protected] for more information.

  9. Jennifer says:

    My daughter is getting migraine alot from zoom calls. She can look at her phone and a tv screen but something about the focusing on the zoom classes in high school triggers a headache. will these also help with blue light from screens?

    • Lori Glover says:

      Our lenses block the blue-green light spectrum, the part which has been shown to bother people who are light sensitive. There is no additional protection in adding additional “blue-blocker” to our lens. All of our non prescription frames now have a lenient 60 day return policy so you can see is SpectraShield is effective for your daughter. 90% of our customers report relief after trying our product. Feel free to email [email protected] for more information and frame recommendations.

  10. Tals says:

    FL-41 LENSES : Work both in the field and front of computer. I need a wrap around sport type prescription shades and indoor prescription as well. Can you provide this?

    • Nicole says:

      Yes, we can fill most single vision, progressive and reader prescriptions. If you are certain that our lenses provide you relief then consider shopping for frames that fit well and then send them to us for a custom lens replacement. Please note that custom orders are not refundable, so be sure that you have tried one of our non-prescription, fully refundable frames before moving forward with an expensive custom order.

  11. Maxine Kaufman-Lacusta says:

    I’m wondering if your lenses include 100% UVA and UVB protection, as I am somewhat photophobic post cataract removal, and want to protect my retina from UV damage, as well. PS – Canadian availability?

    • Nicole says:

      Yes, all of our lenses block 100% UVA/UVB light for the most therapeutic possible lens. And yes, we ship to Canada regularly.

Leave a Reply

Your email address will not be published.

Subscribe to get the latest tips, promotions, and news on new products.

This field is for validation purposes and should be left unchanged.