Did you know …

... that blue light can be both good and bad for you?

Part 12: Did you know …

... that blue light can be both good and bad for you?

Whether we're outdoors or indoors, light waves are constantly affecting us. The effects of a specific part of the visible spectrum of light - are currently the cause of much debate. We need the blue light spectrum for a healthy body and general well-being, but blue light radiation can also be dangerous. One thing we know for certain is that we're exposed to more blue light than ever before due to modern light sources such as LED lighting and the radiation emitted by screens.

What makes blue light so important?

Light has a biological effect on our bodies. This has been confirmed by scientific studies, but we also perceive it ourselves when we feel the sunlight on our skin after a long period of overcast skies. As well as providing pleasant warmth, light also helps regulate our hormone balance. The hormone melatonin plays a major role in regulating our sleep/wake cycle, and the light energy that we require for this process is largely absorbed through our eyes. Blue light is a short-wavelength light.  The photopigment melanopsin is particularly sensitive to this kind of light. It helps keep our biological clocks in sync, keeping us active during the day and, when the natural blue light level is fading with sunset,  making us tired at night. Light therapy makes use of this process to successfully combat winter depression and insomnia.

We know that UV light is involved in the production of vitamins. That's important for our metabolism, so our bodies clearly need blue light to thrive and survive. But what kind of blue light? And how much?

Blue light: What you need to know about?

Too much light in the ultraviolet and blue-violet bands can permanently damage the human eye. As well as leading to painful inflammation of the conjunctiva and cornea, it can also cause damage to the eye's crystalline lens (e.g. cataracts) and especially to the retina (macular degeneration). That's why it's so important to wear sunglasses with 100% UV protection in strong sunshine to properly protect our eyes, especially in situations where there is a lot of glare such as on water or snowy mountain slopes – and that applies to children's eyes, too.

What about frequent indoor exposure to light sources with a high proportion of blue light?

Increasing attention is being paid to the strong blue light component of light-emitting diodes (LEDs) and energy-saving bulbs and the electromagnetic radiation from displays such as smartphones, computer screens, tablets and e-readers.

The good news is that none of the studies carried out so far suggest that using computer displays or staring at these new sources of light for long periods of time damages the retina. And it's important to remember that spending one hour outside on a normal overcast day exposes our eyes to 30 times more blue light than spending one hour inside sitting in front of a screen.

Nonetheless, the fact remains that blue light radiation from light sources or screens can be irritating or tiring for some people's eyes.

ZEISS eyeglass lenses with DuraVision® BlueProtect can help remedy this situation. The clear lenses feature a new lens coating which contains a hard coating and Clean Coat technology to make them easier to clean, as well as a blue filter which attenuates blue light in the 390 to 440 nm band.

That means improved visual comfort for anyone seeking protection against blue light during indoor activities – all without losing the beneficial effects of blue light in the 450 to 500 nm band! Spectacles with DuraVision® BlueProtect can be worn all day long, just like normal spectacles. For all outdoor activities in the sunshine, however, sunglasses or self-tinting lenses such as ZEISS PhotoFusion – both of which offer 100% UV protection – are still the recommended choice.

At a glance: the pros and cons of blue light

Pro Contra
Regulates circadian rhythm (day-night rhythm)
There is a body of evidence to suggest that blue light in the spectrum between 400 and 520 nm with a maximum at 460 nm is important for the proper regulation of melatonin in the body, which influences circadian rhythms (day-night rhythm) and general well-being.
Increases risk of macular degeneration
On the other hand, there is a body of evidence to suggest that long-term exposure to blue-violet light below 460 nm, with a maximum at 440 nm, may contribute to photochemical damage of the retina, increasing the risk of macular degeneration over time (known as the ‘blue light hazard’).
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"ZEISS lenses with DuraVision BlueProtect let you operate all digital devices with better vision."

David Soliva,
Eye Care Professional

Learn more about ZEISS DuraVision BlueProtect and "Blue Light"

DuraVision® BlueProtect by ZEISS: The ZEISS Blue-Violet Light Blocking Solutions.

DuraVision® BlueProtect by ZEISS is a coating specially developed for people who spend a lot of their time indoors and are exposed to blue-violet light from LEDs as well as TV, computer or tablet screens.


Blue Light: the Good and the Bad

How much blue light do we need? And how and when should we be protecting ourselves against it?


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