The weather is finally sunny again, but when you go outside, you realize you’ve forgotten your prescription sunglasses. You never have it with you when you need it most! This is such a familiar and frustrating situation for all spectacle wearers. But are you also familiar with the consequences? Without sunglasses, we have no protection against glare, harmful UV radiation, and potentially harmful blue light. Due to high UV exposure, eyeglasses and especially sunglasses are not just an accessory, but an essential item for good and healthy vision. And if you’re all too familiar with the annoyance of constantly being caught without it, or constantly switching your everyday glasses with sunglasses, it may be time to consider photochromic lenses.
Photochromic lenses automatically adapt to changing light conditions. This means that they are clear and transparent indoors and turn dark as soon as you go outside, and the lenses are exposed to UV radiation. Simply put, they are everyday lenses and sunglasses, all in one. Because the lenses automatically adapt to different light conditions, the eyes are considerably relieved. The glasses are great for everyday use because they provide glare protection in all light conditions. With self-tinting lenses, there’s no need to swap glasses when you’re moving between the outdoors and inside.
In nature, some minerals change color and, in particular, become darker when exposed to UV radiation. Photochromic eyeglass lenses are enhanced with special molecules that react to changing light conditions, triggering a chemical reaction on the surface of the lens. Specifically, the molecules in the material change when exposed to UV radiation and then absorb visible light. This process is reversible, and this means that the lenses become clear again as soon as the UV radiation is no longer present.
Frequent light shifts are exhausting for the eyes. Thanks to the intelligent material and the automatic glare reduction, the eyes are protected in sunlight. In addition, photochromic lenses offer protection from UV radiation and blue light, which is emitted outdoors by the sun and indoors by artificial light sources and digital displays.
For general use, photochromic lenses provide good visual comfort with adequate glare protection and protection from UV radiation and from potentially harmful blue light and can adequately replace sunglasses. However, behind a windshield or even window glass, the UV radiation is often insufficient to darken the lens completely. For this reason, it is advisable to wear a suitable pair of sunglasses on long car journeys.
If I wear my eyeglasses a lot indoors and outdoors - both during the day and in the evening or at night - then self-tinting lenses provide good visual comfort with adequate glare protection.
Indoors, photochromic lenses are transparent and clear and can be used as everyday eyewear without any concerns. In addition, such lenses can be equipped with additional functions such as integrated protection against blue light. Although blue light from digital devices, such as computer screens or even LED interior lighting, does not pose an immediate acute threat to eye health, scientific studies show that it may have an impact on our visual comfort and well-being. These include complaints about a perceived reduction in visual quality, the perception of glare, or subjective visual stress. The new generation of self-tinting lenses from ZEISS is based on integrated blue light protection. When activated, the lenses absorb up to 94 percent of blue light outdoors and up to 50 percent when clear indoors.1
- Photochromic systems are constantly optimized to improve the transition speed from light to dark tint and back again.
- To make self-tinting lenses a fashionable accessory, especially when worn as sunglasses, they now often come in a variety of colors and coatings.
Find out more about ZEISS PhotoFusion X lenses in the press release or consult your local eye care professional.
1. Analyses by Technology and Innovation, Carl Zeiss Vision GmbH, DE 2021. Based on Blue Violet Block (BVB) metric that quantifies the amount of light 400-455nm blocked by PFX Extra Grey 1.6 HC form.