All about Sunglass Lenses

_{Article first published: May 2022
Last update: August 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. It is important for everyone to have a pair of sunglasses, whether they need a prescription or not and regardless of their age. ZEISS was the first company to introduce sunglasses with consistent tint, called UMBRAL lenses, in 1924. 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.

It's important to note that there are two types of sunglasses available: those with prescription lenses for vision correction and those without, known as plano lenses. ZEISS offers both options in their product range so that those who wear glasses don't have to sacrifice style for protection. With a range of customization options available, such as progressive or single vision lenses, mirroring and polarization filters, and modern colors and frames, there's a perfect option for everyone. Here are some tips on how to find the right prescription sunglasses.

Prescription sunglasses basically offer the same vision correction as traditional 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.

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 may 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. Sunglass-level 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.

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, lighter shades, and classic colors like green, brown, and grey are a good choice as they are quite neutral. Your 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.

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.

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.

People who are interested in style and trends prioritize the look of their sunglasses. Not to worry, sunglasses can be easily enhanced with different mirror coatings, regardless of whether they have a prescription or not. The front of the lenses have ultra-thin vacuum layers that are applied through vapor deposition. The layers are optimized in their sequence, texture, and thickness to enhance light reflection on the lens surface with a specific color and intensity. Mirrored sunglasses are not only a fashion statement, but they also help in reducing light intensity in extreme lighting conditions.

If you frequently travel by car or participate in water sports, it's recommended that you wear polarizing sunglasses. These types of sunglasses help to reduce glare caused by sunlight reflecting off of wet roads, snow, or water. This glare can negatively impact vision and potentially lead to dangerous situations. Polarizing lenses are specially designed to minimize these reflections and improve contrast vision. Sunglasses with the appropriate visual strength and specialized tints, like ZEISS DriveSafe lenses, can help individuals identify hazardous conditions while driving. Moreover, polarized lenses, like ZEISS SkyLet, enable people to detect more of their surroundings. For instance, these lenses are useful for fishing as they allow people to see fish beneath the water surface. Conversely, ordinary lenses only allow one to see the water surface and not the things below it due to surface reflection.

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. A pair of children's sunglasses should also protect against UV radiation up to 400 nanometers. In addition, kids' sunglasses should be robust and fit well. Your eye care professional can provide consultation on this.