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All about Sunglass Lenses
Summer, Sun, Eye Protection
Article first published: May 2022
Last update: March 2023
For many, sunglasses are a fashion accessory. But sunglasses have important functions besides the fashion aspect: They provide glare protection from the sun and, most importantly, protection from harmful UV radiation. Therefore, basically, everyone should have a suitable pair of sunglasses at hand, whether with or without a prescription, whether old or young.
Good to know: As early as 1924, ZEISS launched its first sunglasses on the market, the so-called UMBRAL lenses. They were the first sunglass lenses with a consistent tint. Today, the range of sunnies with diverse tints and extras is vast. This article explains the important things to consider when buying the next pair of sunglasses.
First of all, it should be said that there are sunglasses with vision correction (prescription lenses) and sunglasses without vision correction (plano lenses). ZEISS has both variants in its product portfolio. So people who wear glasses don't have to do without fashionable sunglasses with adequate protection. They can customize their sunnies in almost any way imaginable: Progressive or single vision lenses with refinements such as mirroring and polarization filters, modern colors and frames. Here are some tips on how to find the right prescription sunglasses.
Optical sunglasses basically offer the same vision correction as conventional clear prescription glasses. They are manufactured according to the values determined during an eye test by an eye care professional, similar to regular glasses. How do they differ from normal glasses? Through tints in various levels and colors, the sunglasses provide not only visual acuity, but also glare protection – just like any other pair of sunglasses.
A vital purchase criterion for sunglasses: Full UV protection
When it comes to sun protection for the eyes, it's not just about glare protection, but also about protection against invisible ultraviolet (UV) radiation. Exposure to UV radiation without protection can lead to acute, medium-term, or even long-term damage to the body – and the eyes. This includes, for example, sunburn of the cornea or premature aging of the skin around the eyes. You can expect full UV protection from sunglasses from a specialist retailer - if you aren't sure, feel free to ask. Full UV protection up to 400 nm applies to all ZEISS sun protection lenses, whether these are bought with or without a prescription. In fact, it has even been standard for all clear ZEISS lenses since 2018.
Transcription of the video
Question: Does sunlight harm my eyes?
Answer: Sunlight can be pretty dangerous. Many people talk about the dangers of UV radiation when they're in the sun and this also applies to the eyes. UV rays are everywhere when the sun is out. This is even true in the shade, due to the refraction of UV rays. So, you can't really protect yourself. For the skin you can use sunscreen and clothing to cover the different areas. It's much more difficult with the eyes. And just a few people would apply sunscreen to the eye lid and still not have adequate protection for the eyes themselves. In other words: You need suitable sunglasses. There are various quality standards for UV protection these days. The limit is 400 nanometers. This represents an overlapping range that includes parts of blue and blue-violet light. Good sunglasses usually have this as a standard. In 2018 ZEISS took the step of incorporating this UV protection up to 400 nm into transparent normal eyeglass lenses as a standard because not everyone wears sunglasses outside consistently. So, full UV protection up to 400 nm is the best way to protect the eyes and surrounding skin from intense daylight and UV radiation even with clear lenses.
In the video, ZEISS expert Dr. Christian Lappe explains how UV radiation from the sun can harm the eyes. (Length: Min 1:34)
What is important when it comes to the color and tint of sunglasses?
When buying new sunglasses, it's fundamental to consider the tint and filter categories. The selection should correspond to the intended use of the sunglasses and personal visual habits and needs. It's important to avoid lenses that are overly dark or too lightly tinted: For a city walk, for example, light tint levels in category 1 or 2 are recommended, filtering out up to 57 percent or 83 percent of the light, respectively. Category 3 is suitable for beach vacation. These lenses absorb up to 92 percent of the light and provide optimum glare protection on the water or on very sunny days, for example when snow reflects in the mountains. Category 4 absorbs up to 97 percent of the light and is only suitable for special situations, such as hiking in high mountains. Driving a car is not allowed with such a dark tint.

The choice of color depends on when and under what circumstances the colored lenses are most often worn. In everyday life, while driving, during sports, or on special occasions? There are even some colors that can have effects on our physiology and psychology.
For those who wear sunglasses frequently or for a long period of time, not too dark shades, and classic colors like green, brown, and grey are a good choice as they are quite neutral. The nearby eye care professional will be able to offer the best advice regarding this. They know what tint levels, color gradients, filter categories, and colors are available and what these are suitable for. They know what tint levels, color gradients, filter categories, and colors are available and what these are suitable for.

The choice of color depends on when and under what circumstances the sunglasses are most often worn.
Have you ever wondered how the color gets into the sunglasses? There are mainly two ways in which lenses are tinted. While sometimes the material itself is already colored, in other situations clear lenses are dyed in a tinting bath. This depends for example on the used material and if the lenses are with or without prescription.
Sunglasses with adapting tint
People often need two pairs of sunglasses: one less tinted and one darker. Especially those who are active outdoors, enjoy strolling in the city, or are looking for more comfort in everyday life may consider sunglasses with a tint that adapts to the different light conditions. ZEISS AdaptiveSun lenses, for example, have a base tint of 60 percent when there is no sunlight, such as in a retail store, and darken up to 97 percent when there is extreme light intensity. They adapt automatically to all light conditions and ensure broad comfortable vision: outdoors in the sunshine or on cloudy days and indoors. They are also available with a gradient tint, which makes it for example easier to read a menu in the garden of a restaurant. Constantly putting on and taking off sunglasses has thus become a thing of the past.

Sunglasses with adapting tint have a base tint that darkens up when there is extreme light intensity.
Mirror coating – making your sunnies a fashion statement
Style- and trend-conscious people place a special value on the appearance of their sunglasses. No problem, because sunglasses can easily be refined with various mirror coatings – whether these sunglasses are with or without a prescription. The ultra-thin vacuum layers are simply vapor-deposited onto the front of the lenses. These layers are optimized in their sequence, texture, and thickness. The reflection of light on the lens surface is enhanced and literally reflected in a specific, defined intensity and color. In addition to making a fashion statement, such mirrored sunglasses also reduce the intensity of light in extreme lighting conditions.

Sunglasses with mirrors are a fashion statement and help to protect the eyes from UV.
Polarizing sunglass lenses: reduce light reflections and improve contrast vision
Who often travels in a car or anyone practicing water sports should consider polarizing sunglasses. What are olarizing sunglasses good for? Glare from reflected light, caused by sunlight on wet roads, snow, or water, significantly affects visual performance and can even lead to not recognizing dangerous situations in time. Special polarizing lenses reduce these disturbing light reflections and improve contrast vision. With the correct visual acuity – if needed – and specific tints in the sunglasses, it is easier to recognize dangerous situations in road traffic. This is achieved, for example, by ZEISS DriveSafe lenses. However, polarized lenses such as ZEISS SkyLet also ensure that significantly more of the surroundings can be perceived. In water sports such as fishing, they make it easier to see fish below the water surface. With standard lenses on the other hand, the surface reflection means that you usually only see the water surface itself and nothing below.
What sunglasses fit my face?
Essentially, there are six different face shapes, which are usually paired with certain frame shapes.
What to look for when buying sunglasses for children?
So many parents do everything to protect their children from the sun but often forget about the eyes. Children's eyes are in fact very sensitive to UV radiation and therefore also sensitive to the dangers it poses. Studies suggest that by the age of 20 we might have already received 50 percent of our lifetime estimates of UV exposure.1 Therefore, kids should also wear sunglasses as often as possible. Of course, a pair of children's sunglasses must also protect against UV radiation up to 400 nanometers. In addition, kids' sunglasses should be robust and fit well. The nearby eye care professional can provide consultation on this too.

UV protection for the eyes is important at every age.
Source:
1. Green, A. C., et al. (2011). Childhood exposure to ultraviolet radiation and harmful skin effects: epidemiological evidence. Progress in biophysics and molecular biology, 107(3), 349-355 / Meta Study, taking several studies into account.
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