How to choose sunglasses
When buying new sunglasses, you should consider not only how good they look on you, but also how well they protect your eyes from UV radiation. Since there are different lens categories and UV protection levels available, it can sometimes be difficult to understand which sunglasses are best – so let's try to understand it together.
Sunglasses with UV protection
We greatly appreciate and enjoy the sun, but perhaps without even realizing how harmful it can be to us, especially when it comes to our eyes.
Sunlight contains various types of rays, including invisible, high-intensity ultraviolet (UV) rays. Although a small amount of sunlight is beneficial to the body, frequent exposure to UV rays can negatively affect vision — especially if the eyes are not properly protected. There are two types of UV rays that can cause the most damage to the eyes - UVA and UVB rays.
UVA rays – make up about 95% of the UV radiation that reaches the earth. They have a longer wavelength (315-400), and therefore penetrate deeper into tissues (both skin and eyes).
UVB rays – make up about 5% of UV radiation, they are shorter, but with higher intensity (approximately 280 – 315). UVB rays can cause "snow blindness".
Both types of rays can harm the eyes:
- UVB primarily damages the cornea.
- UVA, in the long term, damages deeper eye structures.
The good news is that quality sunglasses with UV protection help maintain eye health in the long run.
Therefore, always choose...
Quality sunglasses with UV protection
UV protection is a special coating applied to sunglasses or prescription glasses lenses to filter or block harmful ultraviolet radiation.
Manufacturers indicate whether the glasses have UV protection. To purchase safe and properly regulated sunglasses, always make sure that the CE mark is also indicated on the glasses.
The CE mark on sunglasses indicates compliance with European Union health, safety, and environmental protection standards, guaranteeing protection against harmful UV rays up to 380–400 nanometers. This mark, found on the temple of the glasses, confirms that the lenses provide adequate UV protection, which is typically categorized from 0 (no protection) to 4 (maximum protection).
Although the CE mark certifies compliance with safety standards, it is recommended to look for the "UV400" or "100% UV Protection" designation, which provides complete protection against both UVA and UVB rays.
Location of the marking:
The CE mark must be clearly visible and indelibly printed on the inside of the sunglass temple.
Safety guarantee:
A genuine CE mark certifies that the glasses have passed the necessary tests to protect the eyes from long-term damage, such as cataracts or snow blindness.
It is also important to understand that lens tint or color is not related to UV protection – the UV filter applied to the lenses is transparent, so even a transparent lens can have UV protection.
Sunglass lens light transmission categories
When choosing sunglasses, we often pay attention to the frame style and lens color, but just as important is the lens tint level or category. This determines how much light the lens blocks and in what conditions it will be most suitable.
Lens categories are divided from 0 to 4, and each is designed for different light intensities — from cloudy days to very bright sun in the mountains or near water. To choose sunglasses that are not only stylish but also safe and comfortable to use, it's worth understanding what these categories actually mean.
- Category 0 — transparent or very light lenses (not intended for sun protection, but as protective glasses, an accessory, or for indoor use). Lens tint: 0 – 10%*
- Category 1 — light lenses for cloudy days (for mild light, twilight training, not suitable for bright sun). Lens tint: 10 – 20%
- Category 2 — medium-dark lenses for glare protection (for city and daily use, spring/autumn). Lens tint: 20 – 43%
- Category 3 — dark lenses for very sunny days (the most common choice). Great for driving, sports, hiking, and everyday use in summer. If activities are planned near/on water, it is recommended to choose these lenses with polarization.>Lens tint: 43 – 80%
- Category 4 — very dark lenses for intense sun (in snowy mountains or on glaciers, on water). This category is not suitable for driving. Lens tint: 80 – 92%
*Percentages vary in different sources.
How to choose for yourself?
For everyday use in Latvia:
Category 3 + UV400 (or with UV 100% marking) - the safest choice.
For sports:
• Running/cycling - Category 2 or 3
• Near water/fishing - Category 3 (preferably with polarization)
• In the mountains - Category 4
Important to remember
• Darker lens ≠ better UV protection.
• Always look for UV400 or 100% UV protection and CE marking.
• Only categories 0–3 are suitable for driving.
A little higher, we mentioned that it is essential to choose this category with polarization. What is polarization?
Polarized sunglasses
Polarization is a special filter in eyeglass lenses that reduces glare (dazzling light) reflecting off horizontal surfaces, such as:
• water
• snow
• wet asphalt
• car bodies and windows
• sand
Polarization improves contrast and visual acuity, thereby enhancing eye comfort and reducing eye fatigue. Road markings, obstacles, and terrain become clearer. Especially useful:
- when driving a car during the day,
- when fishing or on the water (water sports, sailing, boating, etc.),
- in the mountains – mountaineering, skiing, snowboarding, outdoor sports, as well as when there is pronounced sensitivity to bright light.
Does polarization mean better UV protection?
No, polarization and UV protection are two different things. A UV filter protects the eyes from harmful radiation, while polarization reduces a very specific angle of light that creates glare – thereby improving visual comfort.
Sunglasses with photochromic lenses
If you want versatile glasses that can be worn in various conditions, choose sunglasses with photochromic lenses.
Photochromic lenses are eyeglass lenses that automatically change their tint depending on the intensity of ultraviolet (UV) radiation.
How do they work?
Photochromic molecules are embedded in the lens material. Under the influence of UV radiation, they activate and the lens darkens. As UV radiation decreases (e.g., indoors), the lens gradually lightens.
The reaction is chemical and reversible, and usually lasts from a few seconds to a few minutes. Photochromic lenses are also available in different categories, for example, category 0-3, category 2-3, category 2-4
Main advantages of photochromic lenses
1. Automatic adaptation to light
No need to change glasses between indoor and outdoor environments.
2. Comfort in changing conditions
Reduces glare and eye fatigue.
Who are glasses with photochromic lenses suitable for?
Sunglasses with photochromic lenses are a practical solution for those who want versatile glasses. They are suitable for hiking, active recreation, and sports enthusiasts who find it uncomfortable or impractical to carry multiple pairs of glasses with different lenses. For example, when cycling, simultaneous protection from wind, insects, and sun is needed, while maintaining the ability to keep the glasses on even in cloudy weather or at dusk.
These glasses will also be appreciated by people with sensitive eyes, as well as those who want to protect their eyes from UV radiation even on cloudy days.
Limitations:
- They usually don't darken completely in a car, as the windshield blocks most UV radiation.
- They may have a slight residual tint even indoors.
- The speed of the lens's chemical reaction may decrease over time.
- Lenses are usually darker in cold temperatures and slightly lighter in warm temperatures.
Choosing sunglass frames and comfort while wearing
And if you've already reached the point of trying on sunglasses, here are some tips to consider:
• The frame of the glasses should fit snugly around the nose and ears, but they should not press or rub;
• The weight of the sunglasses should be evenly distributed between the ears and nose;
• The frame should be light enough so as not to create excessive pressure or friction at the support points;
• Eyelashes should not touch the frame or lenses;
• Many glasses can be adjusted by carefully fitting them to the bridge of the nose and/or temples.
• Glasses should not slide down when tilting the head;
• If you plan to wear glasses with a helmet/hat, make sure they fit well together.
*Often, Category 4 glasses have side shields designed to cover the gap between the face and the frame. These sides must fit the face very well to prevent bright light and strong wind from entering from the sides. Many manufacturers allow these side shields to be removed or attached. Some models also allow a nose guard to be added.
