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UV400 Protection – The Most Important Feature in Sunglasses
The most important function of sunglasses is to protect the eyes from harmful ultraviolet radiation, or UV radiation. Good sunglasses aren’t just a stylish accessory—they help protect your eyes from long-term UV exposure all year round.
All sunglasses at Ninja.fi feature 100% UV protection (UV400), which effectively filters out both UVA and UVB radiation.
What does UV400 mean?
UV400 means that the sunglasses block virtually all harmful ultraviolet radiation up to a wavelength of 400 nanometers. This covers both UVA and UVB radiation, which can strain and damage your eyes over time.
In other words:
- UV400 = 100% protection against harmful UV radiation
- protects against both UVA and UVB radiation
- is one of the most important features of high-quality sunglasses
A dark lens alone does not protect the eyes. Without UV protection, a dark lens can actually increase the amount of UV radiation reaching the eye, because the pupil dilates in dimmer light.
Why is UV protection important?
Your eyes are exposed to UV radiation whenever you’re outdoors—even on cloudy days. UV radiation is particularly intense in the summer, near water, in the mountains, and in the winter, when snow and ice reflect sunlight.
Long-term exposure to UV radiation can increase the risk of various eye diseases. In addition, intense sunlight can cause eye irritation, dryness, and temporary sensitivity to light.
Good sunglasses help protect your eyes from these harmful effects in everyday use.
Protecting Children’s Eyes
Children’s eyes are particularly sensitive to UV radiation, as the lens of a child’s eye allows more UV radiation to pass through than that of an adult’s eye.
That’s why wearing sunglasses is also recommended for children whenever the weather is sunny. The best protection comes from lenses that are large enough to shield the eyes from light coming from the sides as well.
Sunglasses all year round
Many people wear sunglasses only in the summer, even though UV radiation is present in all seasons. Sunglasses are useful, for example:
- in the summer in bright sunlight
- in winter, due to reflections from snow and ice
- while boating and at the beach
- while driving
- while hiking and enjoying the outdoors
Do the sunglasses meet EU requirements?
Yes. All sunglasses sold on Ninja.fi meet the European Union’s safety requirements for personal protective equipment and the requirements of the applicable sunglasses standard. The CE marking indicates that the manufacturer certifies the product meets the relevant EU safety requirements.
CAT Classification for Sunglasses
UV protection and CAT classification refer to two different things. UV400 indicates how well the sunglasses protect the eyes from harmful UV radiation. The CAT classification, on the other hand, indicates how much visible light the lens transmits—in other words, how dark the lens is.
Therefore, sunglasses can have the same UV400 protection even if their CAT class is different.
| CAT Class | Light Transmittance | Suitable for |
|---|---|---|
| CAT 0 | 80–100% | Clear or nearly clear lenses. For light use and fashion glasses. Not for actual sunny weather. |
| CAT 1 | 43–80% | Cloudy weather and minimal sunlight. |
| CAT 2 | 18–43 | Variable weather conditions and partly cloudy skies. |
| CAT 3 | 8–18 | Normal sunny weather. The most common and recommended category for daily use in Finland. |
| CAT 4 | 3–8 | Extremely bright conditions, such as glaciers and high mountains. Not suitable for driving. |
How do I choose the right CAT category?
For most users, CAT 3 is the best choice. It offers a comfortable experience in bright sunlight and is suitable for driving, the beach, outdoor seating areas, boating, and everyday use.
CAT 4 lenses are designed for extremely bright sunlight and must not be worn while driving due to their darkness.
