FL-41 is a lens tint that was commonly used to manage light sensitivity. However, studies show a wide variance in FL-41 lenses from different vendors. So, are all FL-41, or light sensitivity 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.
Here are pictures of different FL-41 lenses on the same model and in the same lighting. The color of the lens ranges from rust to purple to hot pink, showing significant variation.
Where Did FL-41 Originate From?
FL-41 has a long and complex history. The technology has been in development since the 1980s, originating at the University of Cambridge. Researchers were seeking a solution for individuals who were affected 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 its use for light sensitivity and photophobia applications today.
In early 1990, Dr. Kathleen Digre of the University of Utah began recommending 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 for light-sensitive patients. He began offering the tint to his own patients who had migraine, and some showed improvement in managing light. Fast forward to today, and Dr. Katz has been instrumental in influencing the design of a new, evolutionary lens design: the Avulux Migraine & Light Sensitivity lens.
How Are Axon Optics Glasses Powered by Avulux Different?
As shown in the first few graphs, the level of variation of generic FL-41 tint is wide. Axon Optics powered by Avulux® Migraine and Light Sensitivity Lenses are shown to help people with migraine and light sensitivity and provide consistent results compared to the variations seen in generic lenses. Here are some of the differences you’ll see with Avulux technology:
- Clinically Validated Lens Testing: Avulux lenses have been tested with hundreds of people living with migraine in a clinical setting and tens of thousands of people living with migraine and light sensitivity in the real world. Independent clinical trials have demonstrated that Avulux lenses' precision in filtering harmful blue, amber, and red light while allowing in soothing green light may help people living with migraine.
- More Soothing Green Light: Dark lenses inside can lead to dark adaptation. Avulux lenses filter up to 97% of harmful light wavelengths while allowing in 70% of soothing green light, supporting people with light sensitivity while maintaining color perception.
- Advanced Research: Axon Optics was founded by a neuro-ophthalmologist, photonics researcher, and optical entrepreneur. Avulux continues to invest in research, developing products for those living with migraine and light sensitivity.
- Consistent Color Quality: Generic lenses may range from red, rust, purple, rose, or orange, making it hard to know what you’re getting. Avulux lenses maintain a consistent spectral quality.
- You can see user experiences for insights into these lenses. For more on the use of tinted lenses for migraine and light sensitivity, explore the details on our research page.
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 therapeutic eyeglasses for people living with light sensitivity for over 15 years.
Avulux lenses have been used by thousands of people and absorb up to 97% of harmful blue, amber, and red light, while allowing the soothing green light through. These lenses are proprietary and have been fine-tuned by our experts in migraine and light sensitivity over many years.
Avulux lenses filter more light than FL-41 without distorting your color perception.
The following graphic contains four photos.
- The top left photo displays a photo taken without any light filter placed in front of the camera.
- The top right photo displays a photo taken with the Avulux light filter placed in front of the camera (no color distortion noted)
- The bottom left photo displays a photo taken with a 590nm amber light filter placed in front of the camera (heavy color distortion).
- The bottom right photo displays a photo taken with a 480nm blue light filter placed in front of the camera (heavy color distortion typical of FL-41).
Try Axon Optics powered by Avulux Lenses
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