How Much Blue Light Are Those Lenses Really Reducing?

You’ve likely seen (or will see) different companies claiming their lenses or enhancements reduce a specific or fixed percentage of blue light.  And you’ve probably noticed that SunSync Light-Reactive Lenses do not do that.
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When you hear or read that a lens product filters 90% of blue light it may sound good, but it is in fact, misleading. 

The Problem with Promoting A Fixed Blue Light Reduction Percentage

Blue light is made up of a range of light from 400 – 500 nanometers (nm).  Blue-light-reducing lens products do not provide one, consistent percentage of reduction across the entire spectrum. So, promoting a single percentage of blue light reduction is not the most effective way of explaining product attributes and could be considered misleading. 

Blue-light-reducing products do not provide one, consistent percentage of reduction across the entire spectrum.”

Generally, these products provide the greatest amount of reduction near the 400nm mark and taper off as you progress toward 500nm. So, when you’re told that a product reduces a specific percent of blue light, what you’re not being told is that percentage is either averaged out over the entire blue light range, or that it represents the reduction (usually the greatest amount) at an unspecified wavelength.

Different blue light ranges within the spectrum are associated with different effects. For, example, blue light in the range of 400-430nm has been linked to digital eye strain.

So, if a manufacturer does not specify the amount of reduction by wavelength, they’re failing to communicate the product’s true properties and benefits. If a company tells you their product reduces 75% of blue light, your first question should be, “At what wavelength?” If a patient is complaining of digital eye strain symptoms, you’d want to recommend a lens product that provides superior reduction within that 400-430nm range.

That’s the benefit of using transmittance graphs.

If a company tells you their product reduces 75% of blue light, your first question should be, “At what wavelength?"

What Does A Blue Light Transmittance Graph Tell You?

A transmittance graph allows you to see a product’s exact amount of blue light transmittance and reduction at every point in the blue light spectrum. In other words, transmittance = transparency.
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Below is the transmittance graph for a gray SunSync Drive XT lens. The white line shows you the amount of transmittance in the clear state and the gray line represents the transmittance in the dark state.

How to Read a Blue Light Transmittance Graph

To determine the amount of blue light reduction, select a wavelength along the bottom, then reference up vertically. Referring to the graph above at 400nm, SunSync Drive XT in the activated, dark state allows about 5% of blue light to be transmitted through the lens. That means it’s filtering out 95% of blue light. 
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As previously mentioned, the 400-430nm range is most commonly linked with digital eye strain. From the transmittance graph for SunSync Drive XT, you can accurately assess that SunSync Drive XT provides good defense against digital eye strain.

From the transmittance graph, you can accurately assess that SunSync Drive XT provides good defense against digital eye strain.”

Are Manufacturers Required to Display Blue Light Transmittance Graphs?

No. It’s up to the manufacturer. We share transmittance graphs for SunSync Light-Reactive Lenses because we feel it’s the most accurate and transparent way to explain what our products are doing. So, each SunSync Light-Reactive Lens is tested by an independent third-party company who provides transmittance graphs before they’re made available to the public. 

We share transmittance graphs for SunSync Light-Reactive Lenses because we feel it’s the most accurate and transparent way to explain what our products are doing."

Use Transmittance Graphs to Help You Make the Most Informed Decision

Your patients come to you seeking the best products to alleviate their symptoms. With all the product claims out there, determining the best lens or enhancement choice can be complicated. Insisting on seeing a transmittance graph for the blue light products you recommend is one way you can simplify that process while providing yourself peace of mind that your patients are getting the exact benefit promised in the product claims.  

Key Takeaways:

• Always insist on blue light transmittance graphs for the lens products you dispense. 
• Blue-light-reducing products don’t deliver one, consistent amount of transmittance across the spectrum, so they can’t provide a fixed percentage of reduction.
• If the lens manufacturer won’t supply you with a transmittance graph, question why.
• When you review transmittance graphs, identify where on the blue light spectrum the lens’ major advantage resides.

See the transmittance graphs for each product in the SunSync Light-Reactive Lenses portfolio here.